choosing a 540-598 engine questions

[Jim W]

I have a Hallett flat bottom V-drive with a 396 BBC and runs about 85 MPH. I would like to get into the 110+ MPH area. After looking at adding power to my 396 I found this company WWW.ohiocrankshaft.com
They have short blocks at what looks to be real good prices.
I have 2 questions about these big inch engines.
1--- If I did go with a big inch engine, am I ok with small heads (oval port, iron), new cam (solid) , Vic Jr intake and 850 Holley or Weiand tunnel ram (have one) with new carbs????
As I can afford it I would be adding the correct power parts to fit the engines size. Not looking for a all out engine.
2--- What would be a good choice?? Pro's and con's?
555 cu in $4050
588 cu in $3995
509-540-555-565 cu in $3795
572-598 cu in $4195
620 cu in $4350
I kind of like the 509 or 540 for $3795
So I guess what I am asking is---- is it ok to buy a big incher and build tward the future???
My thinking is to sell my good running 396 for something like $2-2500 and go big.
Thanks all. Be good, Jim

[Jim W]

Sorry bad link
Try this
WWW.ohiocrank.com

[BUSBY]

Sometimes bigger isn't better ... we were running a 468 (454 - .060 over) hurt it ... stepped back to a 440 (427 - .060 over) and it ran quicker.
Your set up has a lot to do with it.
I like the 396/427 ... great motor because the geometry is better due to the wrist pin sitting higher in the piston ... you'll get more RPM than a bigger motor ... the bigger motor should give you more touque though.
I would look into a 4.5 bore, 3.766 crank (your 427/396 crank), 6.135 rod ... you end up with a 479" motor ... a high reving big bore motor ... great set up IMO ... and you can still use your heads & all ... cheaper build for you.

[BUSBY]

you can go to racingjunk.com and get a Merlin block for like $2200 and an eagle crank for like $800 ... rods here at Neil's spam ... http://www2.***boat.com/forums/showthread.php?t=93084&highlight=sdpm
for $200 ... Pistons for about $500 ... Rings/Bearings/timing chain/gaskets/etc $500 ... add an extra $500 for whatever else pops up ...
You're at $4200 ... and you know you have a kick ass deal ... plus you built it so you know it's done right ...
Just my thoughts ... good luck

[cjordan]

Big inch motors need big heads, big flow, BIG cams, and big carbs to make power......which is $ $ $ $ $ $, I know from experience. I had 632" BBC (10.5:1) with fully ported Dart 360 heads (marginal) Dart tunnel ram, 2 X 775 race Demons (for idle, needed to be larger) 280/288@.050 ~.750" lift cam on 115 CL (could have used more cam)...point is, they need to move tons of air! It did make 900HP @6500 on pump gas and 820 ft/# @5000 though... :p

[Havasu47]

Big inch motors need big heads, big flow, BIG cams, and big carbs to make power......which is $ $ $ $ $ $, I know from experience. I had 632" BBC (10.5:1) with fully ported Dart 360 heads (marginal) Dart tunnel ram, 2 X 775 race Demons (for idle, needed to be larger) 280/288@.050 ~.750" lift cam on 115 CL (could have used more cam)...point is, they need to move tons of air! It did make 900HP @6500 on pump gas and 820 ft/# @5000 though... :p
Curious why you went with a 115 LS.....

[cjordan]

Curious why you went with a 115 LS.....
Simple...Idle quality. Had a 272/278@.050 in it on 114 before that cam. When I went to 280/288 on 115 idle was much, much rougher. Big inch motors seem to like wider LS as well...although I couldn't tell you why. Would idle ~900 out of gear. :p sounded nasty with dry to the tip CMI's.!

[Jim W]

I would look into a 4.5 bore, 3.766 crank (your 427/396 crank), 6.135 rod ... you end up with a 479" motor ... a high reving big bore motor ... great set up IMO ... and you can still use your heads & all ... cheaper build for you.
Busby, interesting combo there. I dont know if I have ever seen that before. Which makes it hard to put together a proven parts package. I would much rather copy someones sorted out BBC than try to figure out what will work the best for this combo.
you can go to racingjunk.com and get a Merlin block for like $2200 and an eagle crank for like $800 ... rods here at Neil's spam ... http://www2.***boat.com/forums/show...&highlight=sdpm
for $200 ... Pistons for about $500 ... Rings/Bearings/timing chain/gaskets/etc $500 ... add an extra $500 for whatever else pops up ...
You're at $4200 ... and you know you have a kick ass deal ... plus you built it so you know it's done right ...
Ohio Crankshaft has a 509---565 cu. in. unassembled Merlin kit for $3795 with none or the screwing around chasing down the parts.
And to be honest with ya,
I wouldnt mind having them do the assy. I have put toghether hundreds of motors but these guys are cutting edge and daily assemble Pro-Mod engines. I think they might be a little better at than me.
Lastly,
cjordan, yes I am very aware of the breathing requirements of big inch motors. I am just thinking of using the initial short block as a stepping stone. Adding heads, intake and carbs later.
Soooooo I still have not gotten a reply about a good Flattie set up with one of their kits??
509
540
555
598
Be good, Jim

[Taylorman]

No matter what she says, bigger is better.

[BUSBY]

Busby, interesting combo there. I dont know if I have ever seen that before. Which makes it hard to put together a proven parts package. I would much rather copy someones sorted out BBC than try to figure out what will work the best for this combo.
I was giving you the numbers of a prooven package ... would have given you all of the numbers too if asked ...
I thought you were on a budget from your original post ... but if $$$ isn't an issue, knock yourself out! But like cjordan said:
Big inch motors need big heads, big flow, BIG cams, and big carbs to make power......which is $ $ $ $ $ $
So, to answer your original questions ...
1--- If I did go with a big inch engine, am I ok with small heads (oval port, iron), new cam (solid) , Vic Jr intake and 850 Holley or Weiand tunnel ram (have one) with new carbs???? As I can afford it I would be adding the correct power parts to fit the engines size. Not looking for a all out engine.
If you go with a big inch motor w/o chaning anything else ... you will have poor performance.
2--- What would be a good choice?? Pro's and con's?
I gave you the pro's and con's earlier with a good choice and the reasoning, but you didn't like the suggestion I guess.
So I guess what I am asking is---- is it ok to buy a big incher and build tward the future???
No one here knows what you are wanting to do in the future other than go 110 or so ... so it's hard to answer this question.
I guess my question is to myself, why did I take the time to answer? You've already made up your mind it seems ... and have built 100's of motors to boot!
Good luck to you ...

[Jim W]

Wow busby--- you are a mean person
Be good, Jim

[BUSBY]

Wow busby--- you are a mean person
Be good, Jim
Not mean Jim ... just factual ... I was trying to help ... that's all ...
Sorry if it came off mean ... didn't mean it that way.
you came here asking for opinions ... I gave one from experience trying to answer your question about using your current equipment:
I would look into a 4.5 bore, 3.766 crank (your 427/396 crank), 6.135 rod ... you end up with a 479" motor ... a high reving big bore motor ... great set up IMO ... and you can still use your heads & all ... cheaper build for you.
You came back with:
I dont know if I have ever seen that before. Which makes it hard to put together a proven parts package. I would much rather copy someones sorted out BBC than try to figure out what will work the best for this combo.
and:
And to be honest with ya, I wouldnt mind having them do the assy. I have put toghether hundreds of motors but these guys are cutting edge and daily assemble Pro-Mod engines. I think they might be a little better at than me.
Sorry, maybe your response to an honest answer from someone who was trying to help wasn't taken as being very nice as well.
Again ... not trying to be mean ... just trying to help.
Good luck.
Brian

[MikeF]

God Brian.........your such an ass. :crossx: :D

[steelcomp]

I agree with Brian, 100%. He just answered Jim W's question, and after reading the thread, I thought, "gee...the guy asks a question, gets a well thought out answer, then proceeds to dis the answer. Whydya ask? You already seem to know the answer, and you're obviously FAR more experienced than the rest of us."
BTW...bigger is definately not better in a small boat like your flatty. Big bore, short stroke combinations like Brian was talking about are readily "proven" combinations. Well, at least among those who aren't interested in "bragging" numbers, or who think for themselves.
Ah, hell, Brian, WTF do we know? :rolleyes:
Jim W...you sound like the kind of guy who would complain about wanting to get drunk and laid, and after someone brought you a girl and handed you a bottle of booze, you'd complain because they didn't pull her panties down and uncork the bottle!
Good luck! :D

[Carnivalride]

Sometimes bigger isn't better ... we were running a 468 (454 - .060 over) hurt it ... stepped back to a 440 (427 - .060 over) and it ran quicker.
Your set up has a lot to do with it.
I like the 396/427 ... great motor because the geometry is better due to the wrist pin sitting higher in the piston ... you'll get more RPM than a bigger motor ... the bigger motor should give you more touque though.
I would look into a 4.5 bore, 3.766 crank (your 427/396 crank), 6.135 rod ... you end up with a 479" motor ... a high reving big bore motor ... great set up IMO ... and you can still use your heads & all ... cheaper build for you.
Busby,
Out of curiosity why did you recommend the 6.135” long rod for this 479cid deal? I looked at doing something similar to this and was going to use a 6.385” long rod and 1.520” wrist pin height pistons (stock rod 4.25 stroke) to save a little weight and cash (off the shelf pistons). If I figured right you would still have .012” to deck the block for a “zero” deck height. Do you not like changing the rod ratio from 1.629 to 1.695 or is there some other reason I didn’t consider? Just asking.
Loren

[WETTE VETTE]

If you decide to go with a tall deck motor I have a complete induction system for sale that includes flame arrestor, BIG Nickerson carb, spacer, regulator, fuel lines, throttle linkage plate and match ported Dart single plane intake. I ran it on my 10:1 598 and it worked great! I am going to a tunnel ram and would like to sell the single carb set up. Let me know if interested and good luck!
Craig

[blowngas]

Flats seem to like a high rpm engine----big bores and small strokes seem to be the hot ticket in these boats

[BUSBY]

Busby,
Out of curiosity why did you recommend the 6.135” long rod for this 479cid deal? I looked at doing something similar to this and was going to use a 6.385” long rod and 1.520” wrist pin height pistons (stock rod 4.25 stroke) to save a little weight and cash (off the shelf pistons). If I figured right you would still have .012” to deck the block for a “zero” deck height. Do you not like changing the rod ratio from 1.629 to 1.695 or is there some other reason I didn’t consider? Just asking.
Loren
Loren ... got your PM ... I was trying to give the guy a direction where he could save some cash ... I thought he was on a budget from the way the original post sounded ... could find the 454 rods for cheap.

[BUSBY]

Flats seem to like a high rpm engine----big bores and small strokes seem to be the hot ticket in these boats
That's why I was trying to help him with what he had ... big bore high RPM motor ...

[BUSBY]

Ah, hell, Brian, WTF do we know? :rolleyes:
exactly ... I'm just another guy tryin' to make the other guy look slow ... maybe I should call the guys who have "proven packages" :messedup:

[Carnivalride]

Loren ... got your PM ... I was trying to give the guy a direction where he could save some cash ... I thought he was on a budget from the way the original post sounded ... could find the 454 rods for cheap.
I understand the budget thing. :cry: Looking forward to seeing your thoughts on the rest of the PM. :idea:
Loren

[Carnivalride]

exactly ... I'm just another guy tryin' to make the other guy look slow ... maybe I should call the guys who have "proven packages" :messedup:
Heck somebody's got to design and build one of these "packages" so they can stick it in a boat and PROVE'disprove it. :rollside: I know I've disproved a couple over my 14 years with this boat know. :cry: :cry: :cry:

[bigkatboat]

Loren, I've told you about the 14-71, 427 +.030" deal. It works and 'almost no one believes', but it's OK. George

[Carnivalride]

Loren, I've told you about the 14-71, 427 +.030" deal. It works and 'almost no one believes', but it's OK. George
George,
Yes I have that one! I have it with timing specs, injector sizes and both cams you had recommended with it. But I didn't think that it would work for a dual purpose boat and pulling the kids tubing. If I can tune this boat to run low 10's/high 9's with the engine that's currently in it, it's done for several years. If I get a shot at another go around in the future then YES I'm considering the 8.0 class and your boat set up/ engine combination is one I would seriously consider. But for now if my boat is competitive in the 10sec class and can pull the kids tubing on av-gas I'm done. Just curious on others' ideas.
Loren

[396_WAYS_TO_SPIT]

Nitrous! Its on tap when you need the hp :D :D plus you dont have to use it with the kids on the tube :p :p

[fc-pilot]

Hi George and Loren,
The issue with the question of big inch (598'ish) compared to the smaller motor has to do more with the whole package of motor, gears and boat setup. The two of you understand that better than I do, but I am afraid that Jim is hoping for a canned answer of "Go Big". The truth is if you can afford the big inches and have heads and induction that can support them it will unquestionably make more power than the little motor. The issue is we are not racing dyno's, but have to adapt the boats setup to the new power. There are many on this board that know more than I. The real issue is knowing what you (JIM) want to do with your boat? Until the people that can help know that, they are stuck as far as giving you good advice.
Paul

[BUSBY]

Hi George and Loren,
The issue with the question of big inch (598'ish) compared to the smaller motor has to do more with the whole package of motor, gears and boat setup. The two of you understand that better than I do, but I am afraid that Jim is hoping for a canned answer of "Go Big". The truth is if you can afford the big inches and have heads and induction that can support them it will unquestionably make more power than the little motor. The issue is we are not racing dyno's, but have to adapt the boats setup to the new power. There are many on this board that know more than I. The real issue is knowing what you (JIM) want to do with your boat? Until the people that can help know that, they are stuck as far as giving you good advice.
Paul
Thank you Paul for visiting this thread ... and I have to apologize to Jim for being "mean" ... if that's how he took it ...
There is no answer for going "big" on the bottom end and not on the top ... that was the point I was trying to help on ... he said that he wanted to do this ... I was trying to help.
He will actually make more HP (proven by numerous builds in major Mag's like Car Craft, Super Chevy & Hot Rod) by going with a big bore, short stroke, high reving BBC rather than a mountian motor bottom end with his current configuration.
If he wants to spend the money for heads, intake, etc. ... then a bigger motor setup would be looked at ...
But lemme ask this ... why would Top Alcohol Dragsters be running 450" Brad Anderson engines @ 10,000 rpm's if cubes were the answer?
Again ... Jim ... just tryin' to save you some cash ... no need to buy big cubes, I like your basic setup ... just think your current engine might fit your needs w/o spending a lot of extra cash ...
Again, good luck with your build ...
BB

[396_WAYS_TO_SPIT]

But lemme ask this ... why would Top Alcohol Dragsters be running 450" Brad Anderson engines @ 10,000 rpm's if cubes were the answer?
BB
Isnt that the truth;)

[Carnivalride]

To all involved,
I wasn't try to stir the pot here when I asked my original question about the rods. I was just asking if Busby liked the original 427 r/s ratio or if it was something else. I guess I figured if your looking into aftermarket blocks then a few bucks more for aftermarket rods in an "off the shelf length" wouldn't be a big deal.
Busby,
Out of curiosity why did you recommend the 6.135” long rod for this 479cid deal? I looked at doing something similar to this and was going to use a 6.385” long rod and 1.520” wrist pin height pistons (stock rod 4.25 stroke) to save a little weight and cash (off the shelf pistons). If I figured right you would still have .012” to deck the block for a “zero” deck height. Do you not like changing the rod ratio from 1.629 to 1.695 or is there some other reason I didn’t consider? Just asking.
Loren
As far as budget and bang for the buck it's different for everybody. What some people call affordable isn't for me and for others it's pocket change. As far as this thread I was just trying listen to someones ideas and understand their reasoning.
Loren

[BUSBY]

Loren ... I don't think anyone thought you were stirring the pot ... using a shorter 454 rod will assist with reliability/pump gas usage ... using the 427 piston will give you better geometry w/ rod angle which will give you a higher rpm band with equal overall performance usability ...
Things I factor in ... the larger diameter of the piston, the more force it takes to move it from TDC or BDC ... these forces impede crank speed.
To get better piston acceleration you need a small rod angle.
Piston acceleration ~ sin^2(stroke/rod length)
It just works out that short stroke engines have a small rod angle because they are used in engines with the same deck height as ones with long strokes(427 & 454 ... 350 & 383). For instance a 383 w/ a 6" rod has a rod angle of 38.8* and a 350 w/ a 5.7" rod has and angle of 37.62* So a longer stroke 383 has one more degree of rod angle. On the other hand a factory 400 sbc is 42.5*
For big blocks a 502 BBC has a rod angle of 40.69* and a 427 BBC is 37.8* Obviously BBC pistons weigh more so that impedes rotation, but they also make more power.
The other thing that impedes crank speed is friction. Obviously if you're not moving as far your making less total friction force.
Stress analysis in the rod shows that
axial stress = (mass of piston* acceleration of piston)/(cross sectional area of piston)
Buckling stress is a function of rod geometry and I won't get into that.
So this all means that shorter rods put less stress on the rods and apply less resistance force on the crank.
Another useful piece of information is average piston speed which is also proportional to intake/exhaust air velocity.
Mean speed = 2*Stroke*RPM
Therefore a short stroke has a lower air velocity. This is generally not the greatest for wet manifolds, because the fuel tends to fall out of the air. Short strokes also tend to fill the cylinders better at high RPM. So building a power band from 4000 to 7500 is the result ... where most of us drive our boats on lakes and rivers. Having a smaller rod angle allow quicker RPM's ... another thing to factor in that we like ...
The biggest factor is the valve train for crank speed. Valves can only go up and down so fast when they are being held by conventional springs. That is why F1 engines use tiny little air bags. But that's a whole new thread topic.
On the other hand, a longer stroke mechanically provides more torque.
Torque = Force * Length.
So IMO to make the most awesome package around you need a short stroke big bore short rod low friction mofo ... a 479" BBC ... :rolleyes:
But what do I know ... I'm not selling engines ... just build them for fun:boxed: I've already wasted too much of my time for someone who's already made up their mind IMO ...
Again Jim ... just tryin' to help out ...
BB

[BUSBY]

insetad of editing ... after rereading the post ... found some little things, well, in error:
Crank friction also depends on inside the cylinders, you need a co-efficient of friction between the cylinder walls and the rings; and then you need to find out the weight of the pistons. Ffr=uFn.
With respect to this equation: Torque = Force * Length
The equation T=Fxd depends on an axis of rotation (pivot point). In the engine, the pivot point on the crankshaft would hardly change the torque because the head of the piston is in a stationary position (kinda sorta), so the T=Fxd is somewhat neligable.
Nit Picking ...

[cstraub]

Loren ... I don't think anyone thought you were stirring the pot ... using a shorter 454 rod will assist with reliability/pump gas usage ... using the 427 piston will give you better geometry w/ rod angle which will give you a higher rpm band with equal overall performance usability ...
Things I factor in ... the larger diameter of the piston, the more force it takes to move it from TDC or BDC ... these forces impede crank speed.
To get better piston acceleration you need a small rod angle.
Piston acceleration ~ sin^2(stroke/rod length)
It just works out that short stroke engines have a small rod angle because they are used in engines with the same deck height as ones with long strokes(427 & 454 ... 350 & 383). For instance a 383 w/ a 6" rod has a rod angle of 38.8* and a 350 w/ a 5.7" rod has and angle of 37.62* So a longer stroke 383 has one more degree of rod angle. On the other hand a factory 400 sbc is 42.5*
For big blocks a 502 BBC has a rod angle of 40.69* and a 427 BBC is 37.8* Obviously BBC pistons weigh more so that impedes rotation, but they also make more power.
The other thing that impedes crank speed is friction. Obviously if you're not moving as far your making less total friction force.
Stress analysis in the rod shows that
axial stress = (mass of piston* acceleration of piston)/(cross sectional area of piston)
Buckling stress is a function of rod geometry and I won't get into that.
So this all means that shorter rods put less stress on the rods and apply less resistance force on the crank.
Another useful piece of information is average piston speed which is also proportional to intake/exhaust air velocity.
Mean speed = 2*Stroke*RPM
Therefore a short stroke has a lower air velocity. This is generally not the greatest for wet manifolds, because the fuel tends to fall out of the air. Short strokes also tend to fill the cylinders better at high RPM. So building a power band from 4000 to 7500 is the result ... where most of us drive our boats on lakes and rivers. Having a smaller rod angle allow quicker RPM's ... another thing to factor in that we like ...
The biggest factor is the valve train for crank speed. Valves can only go up and down so fast when they are being held by conventional springs. That is why F1 engines use tiny little air bags. But that's a whole new thread topic.
On the other hand, a longer stroke mechanically provides more torque.
Torque = Force * Length.
So IMO to make the most awesome package around you need a short stroke big bore short rod low friction mofo ... a 479" BBC ... :rolleyes:
But what do I know ... I'm not selling engines ... just build them for fun:boxed: I've already wasted too much of my time for someone who's already made up their mind IMO ...
Again Jim ... just tryin' to help out ...
BB
Busby,
Excellent post.
Jim W.
To accomplish your goals you have a couple routes you can go but $$$ will determine what you want to do.
If it is a lite boat and $$$ are no problem, then a high winding "small inch" BB will work very well. These love rpm to make power and for competition stuff are very good combinations. Negative is high rpm means more costly parts and a serious maintenance program.
If the boat is heavy and your on a budget a big inch mill works good. Can pull more prop, run at a lower rpm and not have an engine that needs to be looked at and checked out constantly. Parts don't have to be the best but initial cost will still be hefty. More user friendly for family and friends.
Chris

[BUSBY]

Busby,
Excellent post.
Wow ... from you ... I take that as a big complement! Thanks!
I feel better now. :D

[cstraub]

Don't put to much in a fella from TN that just got running water in the house and individualy wrapped cheese slices last week!!!!

[BUSBY]

Don't put to much in a fella from TN that just got running water in the house and individualy wrapped cheese slices last week!!!!
:D
wrapped cheese? what's that?
shoot ... I'm just glad that the ground out here stops shaking once & a while so I still can work on an enging w/o screwing it up ... they say I should be falling into the ocean at any minute ... :p

[Carnivalride]

Loren ... I don't think anyone thought you were stirring the pot ... using a shorter 454 rod will assist with reliability/pump gas usage ... using the 427 piston will give you better geometry w/ rod angle which will give you a higher rpm band with equal overall performance usability ...
Things I factor in ... the larger diameter of the piston, the more force it takes to move it from TDC or BDC ... these forces impede crank speed.
To get better piston acceleration you need a small rod angle.
Piston acceleration ~ sin^2(stroke/rod length)
It just works out that short stroke engines have a small rod angle because they are used in engines with the same deck height as ones with long strokes(427 & 454 ... 350 & 383). For instance a 383 w/ a 6" rod has a rod angle of 38.8* and a 350 w/ a 5.7" rod has and angle of 37.62* So a longer stroke 383 has one more degree of rod angle. On the other hand a factory 400 sbc is 42.5*
For big blocks a 502 BBC has a rod angle of 40.69* and a 427 BBC is 37.8* Obviously BBC pistons weigh more so that impedes rotation, but they also make more power.
The other thing that impedes crank speed is friction. Obviously if you're not moving as far your making less total friction force.
Stress analysis in the rod shows that
axial stress = (mass of piston* acceleration of piston)/(cross sectional area of piston)
Buckling stress is a function of rod geometry and I won't get into that.
So this all means that shorter rods put less stress on the rods and apply less resistance force on the crank.
Another useful piece of information is average piston speed which is also proportional to intake/exhaust air velocity.
Mean speed = 2*Stroke*RPM
Therefore a short stroke has a lower air velocity. This is generally not the greatest for wet manifolds, because the fuel tends to fall out of the air. Short strokes also tend to fill the cylinders better at high RPM. So building a power band from 4000 to 7500 is the result ... where most of us drive our boats on lakes and rivers. Having a smaller rod angle allow quicker RPM's ... another thing to factor in that we like ...
The biggest factor is the valve train for crank speed. Valves can only go up and down so fast when they are being held by conventional springs. That is why F1 engines use tiny little air bags. But that's a whole new thread topic.
On the other hand, a longer stroke mechanically provides more torque.
Torque = Force * Length.
So IMO to make the most awesome package around you need a short stroke big bore short rod low friction mofo ... a 479" BBC ... :rolleyes:
But what do I know ... I'm not selling engines ... just build them for fun:boxed: I've already wasted too much of my time for someone who's already made up their mind IMO ...
Again Jim ... just tryin' to help out ...
BB
Jim,
That was a good post! :hammer2:
I little more tecnical than I expected on an open post but all good points. :cool: :cool:
Loren

[fc-pilot]

Very good points for sure. The issue for Jim will be how much ca$h he can reasonably spend.
About the Top Alcohol Dragsters running 450 cubic inches, they are only allowed to run 466 anyway (unless they want to add weight, which at the rate that they make them increase it shoots them in the foot). Just more useless info.
Paul

[Hipshot]

I can almost gaurantee you BUSBY that if alcohol dragsters were allowed to run 540+ inch motors without weight penalties being put on them they would.

[Brian]

Personally, I'd build a 565 on a 10.2 block with a 6.535 rod and call it a day. Since you don't need lots of torque, keep the stroke to 4.25, add big heads + big cam and make some HP! Engine geometry with that combo is very nice, decent rod ratio (by Chebby standards at least), good piston stability, good ring stack, happy motor that should live a while...
:D
ps: Be careful going big if you intend to run the motor for the long run. Big cranks and long rods are fun to talk about but compromise piston geometry that's important for things like oil control and ring sealing...

[steelcomp]

Brian, that was a great post. I'd like to offer some of my experience, here if I may. While mechanically, you're dead on, there are other issues regarding rod length, and rod/stroke ratio "n" that play in, here, that I feel should be adressed. Not to say which is better or worse, as that debate has, and will go on forever, just offering more info. Mind you, some of this will be cut and paste to save me hours of typing.
The length of the rod is less an issue than is the ratio. There is a small range of ratios for most conventional piston engines: the rod is going to be between roughly 1.4 and 2.2 times the stroke length. The rod can't be the same length as the stroke, and rods much longer than twice the stroke make the motor very tall, and, although used for racing,
aren't real practical. A greater rod angle will occur by installing a shorter rod or by increasing the stroke (smaller value of “n”). A reduced angle will occur with a longer rod or a shorter stroke. (larger value of “n”) When the “n” ratio value becomes smaller, it has several effects. This is a brief summary of the mechanical effects.
(here's the cut and paste)
Motors with low values of “n” (proportionately short rods or long strokes) typically exhibit the following characteristics (compared to high “n” motors):
» physically shorter top-to-bottom & left-to-right (more oil pan, header, and air cleaner clearance)
» lower block weight (short deck vs. tall deck)
» higher level of vibration
» shorter pistons, measured from the pin center to the bottom of the skirt
» greater wear on piston skirts and cylinder walls
» slightly higher operating temperature & oil temperature due to friction
There are also differences in how the motor breathes:
» intake vacuum rises sooner ATDC, allowing bigger carburetors or intake port runner & plenum volumes to be used without loss of response
» on the negative side, a small or badly designed port will “run out of breath” sooner
» piston motion away from BDC is slower, trapping a higher percentage of cylinder volume, making the motor less sensitive to late intake valve closing (hot cams)
Spark advance is also affected:
» earlier timing (more advance) is required, as the chamber volume is larger (piston is farther from TDC) at the same point of rotation
» the motor may also be less knock-sensitive, as the chamber volume increases more rapidly ATDC, lowering combustion pressure (this is useful for nitrous & supercharged motors)
Here's some pros and cons regarding long vs/ short rod. (more cut and paste)
Long rods
Pro:
» Provides longer piston dwell time at & near TDC, which maintains a longer state of compression by keeping the chamber volume small. This has obvious benefits: better combustion, higher cylinder pressure after the first few degrees of rotation past TDC, and higher temperatures within the combustion chamber. This type of rod will produce very good mid to upper RPM torque.
» The longer rod will reduce friction within the engine, due to the reduced angle which will place less stress at the thrust surface of the piston during combustion. These rods work well with numerically high gear ratios and lighter vehicles.
» For the same total deck height, a longer rod will use a shorter (and therefore lighter) piston, and generally have a safer maximum RPM.
Con:
» They do not promote good cylinder filling (volumetric efficiency) at low to moderate engine speeds due to reduced air flow velocity. After the first few degrees beyond TDC piston speed will increase in proportion to crank rotation, but will be biased by the connecting rod length. The piston will descend at a reduced rate and gain its maximum speed at a later point in the crankshaft’s rotation.
» Longer rods have greater interference with the cylinder bottom & water jacket area, pan rails, pan, and camshaft - some combinations of stroke length & rod choice are not practical.
Short rod
Pro:
» Provides very good intake and exhaust velocities at low to moderate engine speeds causing the engine to produce good low end torque, mostly due to the higher vacuum at the beginning of the intake cycle. The faster piston movement away from TDC of the intake stroke provides more displacement under the valve at every point of crank rotation, increasing vacuum. High intake velocities also create a more homogenous (uniform) air/fuel mixture within the combustion chamber. This will produce greater power output due to this effect.
» The increase in piston speed away from TDC on the power stroke causes the chamber volume to increase more rapidly than in a long-rod motor - this delays the point of maximum cylinder pressure for best effect with supercharger or turbo boost and/or nitrous oxide.
» Cam timing (especially intake valve closing) can be more radical than in a long-rod motor.
Con:
» Causes an increase in piston speed away from TDC which, at very high RPM, will out-run the flame front, causing a decrease in total cylinder pressure (Brake Mean Effective Pressure) at the end of the combustion cycle.
» Due to the reduced dwell time of the piston at TDC the piston will descend at a faster rate with a reduction in cylinder pressure and temperature as compared to a long-rod motor. This will reduce total combustion.
Now you know why you see more Fords (typically with "n" numbers in the 1.7 range like the 289, 302, 351W, 429/460) with smaller ports and carbs as compared to GM products, which have few engines with anything higher than 1.6. (The 327 has an "n" of 1.76, 396/427 has 1.61, and the 454 has a 1.53)
I'll continue this more later.

[BUSBY]

Busby, interesting combo there. I dont know if I have ever seen that before. Which makes it hard to put together a proven parts package. I would much rather copy someones sorted out BBC than try to figure out what will work the best for this combo.
I have put toghether hundreds of motors but these guys are cutting edge and daily assemble Pro-Mod engines. I think they might be a little better at than me.
Big bore, short stroke combinations like Brian was talking about are readily "proven" combinations. Well, at least among those who aren't interested in "bragging" numbers, or who think for themselves.
Wow busby--- you are a mean person
God Brian.........your such an ass. :crossx: :D
Busby,Excellent post.
That was a good post! I little more tecnical than I expected on an open post but all good points. :cool: :cool:
Very good points for sure.
I like this one best Scott:
Ah, hell, Brian, WTF do we know? :rolleyes:

[BUSBY]

Brian, that was a great post. I'd like to offer some of my experience, here if I may. While mechanically, you're dead on, there are other issues regarding rod length, and rod/stroke ratio "n" that play in, here, that I feel should be adressed. Not to say which is better or worse, as that debate has, and will go on forever, just offering more info. Mind you, some of this will be cut and paste to save me hours of typing.
The length of the rod is less an issue than is the ratio. There is a small range of ratios for most conventional piston engines: the rod is going to be between roughly 1.4 and 2.2 times the stroke length. The rod can't be the same length as the stroke, and rods much longer than twice the stroke make the motor very tall, and, although used for racing,
aren't real practical. A greater rod angle will occur by installing a shorter rod or by increasing the stroke (smaller value of “n”). A reduced angle will occur with a longer rod or a shorter stroke. (larger value of “n”) When the “n” ratio value becomes smaller, it has several effects. This is a brief summary of the mechanical effects.
(here's the cut and paste)
Motors with low values of “n” (proportionately short rods or long strokes) typically exhibit the following characteristics (compared to high “n” motors):
» physically shorter top-to-bottom & left-to-right (more oil pan, header, and air cleaner clearance)
» lower block weight (short deck vs. tall deck)
» higher level of vibration
» shorter pistons, measured from the pin center to the bottom of the skirt
» greater wear on piston skirts and cylinder walls
» slightly higher operating temperature & oil temperature due to friction
There are also differences in how the motor breathes:
» intake vacuum rises sooner ATDC, allowing bigger carburetors or intake port runner & plenum volumes to be used without loss of response
» on the negative side, a small or badly designed port will “run out of breath” sooner
» piston motion away from BDC is slower, trapping a higher percentage of cylinder volume, making the motor less sensitive to late intake valve closing (hot cams)
Spark advance is also affected:
» earlier timing (more advance) is required, as the chamber volume is larger (piston is farther from TDC) at the same point of rotation
» the motor may also be less knock-sensitive, as the chamber volume increases more rapidly ATDC, lowering combustion pressure (this is useful for nitrous & supercharged motors)
Here's some pros and cons regarding long vs/ short rod. (more cut and paste)
Long rods
Pro:
» Provides longer piston dwell time at & near TDC, which maintains a longer state of compression by keeping the chamber volume small. This has obvious benefits: better combustion, higher cylinder pressure after the first few degrees of rotation past TDC, and higher temperatures within the combustion chamber. This type of rod will produce very good mid to upper RPM torque.
» The longer rod will reduce friction within the engine, due to the reduced angle which will place less stress at the thrust surface of the piston during combustion. These rods work well with numerically high gear ratios and lighter vehicles.
» For the same total deck height, a longer rod will use a shorter (and therefore lighter) piston, and generally have a safer maximum RPM.
Con:
» They do not promote good cylinder filling (volumetric efficiency) at low to moderate engine speeds due to reduced air flow velocity. After the first few degrees beyond TDC piston speed will increase in proportion to crank rotation, but will be biased by the connecting rod length. The piston will descend at a reduced rate and gain its maximum speed at a later point in the crankshaft’s rotation.
» Longer rods have greater interference with the cylinder bottom & water jacket area, pan rails, pan, and camshaft - some combinations of stroke length & rod choice are not practical.
Short rod
Pro:
» Provides very good intake and exhaust velocities at low to moderate engine speeds causing the engine to produce good low end torque, mostly due to the higher vacuum at the beginning of the intake cycle. The faster piston movement away from TDC of the intake stroke provides more displacement under the valve at every point of crank rotation, increasing vacuum. High intake velocities also create a more homogenous (uniform) air/fuel mixture within the combustion chamber. This will produce greater power output due to this effect.
» The increase in piston speed away from TDC on the power stroke causes the chamber volume to increase more rapidly than in a long-rod motor - this delays the point of maximum cylinder pressure for best effect with supercharger or turbo boost and/or nitrous oxide.
» Cam timing (especially intake valve closing) can be more radical than in a long-rod motor.
Con:
» Causes an increase in piston speed away from TDC which, at very high RPM, will out-run the flame front, causing a decrease in total cylinder pressure (Brake Mean Effective Pressure) at the end of the combustion cycle.
» Due to the reduced dwell time of the piston at TDC the piston will descend at a faster rate with a reduction in cylinder pressure and temperature as compared to a long-rod motor. This will reduce total combustion.
Now you know why you see more Fords (typically with "n" numbers in the 1.7 range like the 289, 302, 351W, 429/460) with smaller ports and carbs as compared to GM products, which have few engines with anything higher than 1.6. (The 327 has an "n" of 1.76, 396/427 has 1.61, and the 454 has a 1.53)
I'll continue this more later.
Ah hell Scott ... oh nevermind! :D :D :D

[steelcomp]

To continue this...
The ratio of the 396/427 and 454 is borderlline practical for the street, and only make good power because of their big intake ports.
Lets look at how rod length effects intake effeciency. An “n” value of 1.75 is considered “ideal” by some respected engine builders, if the breathing is optimized for the design. Except for purpose-built racing engines, most other projects are compromises where 1.75 may not produce the best results. There will be instances where the choice of stroke or rod has not been made, but the intake pieces (carburetor, manifold, and head) have been selected. Some discretion exists here for making the rod and/or stroke choice compatible with the existing intake. The “n” value can be used to compensate for less-than-perfect match of intake parts to motor size & speed. The reverse is also possible: the lower end is done, but there are still choices for the top end. Again, the “n” value can be used as a correction factor to better “match” the intake to the lower end.
So, IN GENERAL, we can summarize that engines with Low “n” numbers (short rods in relation to stroke, between 1.45 - 1.75) will tend to like large intake port volume vs. motor size, they'll perfer single-plane or 360° intake manifolds, large carburetor vs. engine size, moderate engine speed, and if we were talking cars, taller axle ratios. On the other hand, enginrs with higer "n" numbers (longer rods in relation to stroke, beteween 1.75-2.1) will be more compatible with small intake port volume vs. motor size, they'll like dual-plane 180° intake manifolds, small carburetors vs. engine size, and higher engine speeds. Again. if we were talking cars, we'd be talking lower axle ratios, as well.
I was also wondering about the rod angle info you posted. I was always told that the angle was figured with a crank at 90* ATDC. Are you getting your numbers at max thrust? (Rod at 90* to the journal...usually about 70-76 deg. crank rotation) To get the rod angle I'm familiar with, you use this formula: Stroke/ (rod length*2) = sin of rod angle. Then I just use a scientific calculator to get the angle. I think that anything above about 17* is asking for trouble, and is going to require a pretty strong rod and bolts. BB Chev. 396/427 is at 18*, and the 454 is 19*! There is a LOT of force on the major thrust surface of the piston in a BB Chev...one of the big draw backs of short rods. They need to be very strong w/ good bolts in any performance app. That's why the "big" dimple rods came w/ 7/16 Boron bolts. ONe of the reasons the 400 SBC was such a dog is due to it's 1.46 "n" and it's 20* rod angle. A 6" rod is a MUST for any performance 400 rebuild.
OK...I'm done with this for now...I hope this helps shed some light on why certain packages work the way they do. I know it was a long read, and there's a lot more info on the subject, but in closing, let me say this. The most highly researched engine development program in any racing venue is, IMO, NHRA Pro Stock. The most successful Pro Stock motors out there are running a rod ratio in the area of 1:7:1. BIG bore, SHORT stroke, but with a rod ratio in that 1.7 range. Something to think about.

[steelcomp]

Sorry...couldn't resist. :rolleyes: Gimme a break...I can't afford to use any of this stuff, so at least I can share it. Besides, you started it. LOL!! :D :D :D

[steelcomp]

Ah hell Scott ... oh nevermind! :D :D :DLOL!! :p

[cjordan]

Steelcomp:
Excellent post! Here are the specs on my old 632"
4.75" X 4.60" bore, 6.70" Rod...pistons were very short....I didn't build it just giving you the specs. Motor was good to 8200 according to the builder, but I never ran it anywhere near there.....6900 on the Dyno.

[BUSBY]

Scott ... this is what is fun about posting with you ... being able to share information that some like to read ... but that I find in the lost notes in my brain ... things I don't use anymore ... sometimes a post comes up & BAM ... all of those trial engines and wasted $$$ from my past can help someone else ...
Let's review what has been said:
I have a Hallett flat bottom V-drive with a 396 BBC and runs about 85 MPH. I would like to get into the 110+ MPH area. After looking at adding power to my 396 I found this company
If I did go with a big inch engine, am I ok with small heads (oval port, iron), new cam (solid) , Vic Jr intake and 850 Holley or Weiand tunnel ram (have one) with new carbs????
As I can afford it I would be adding the correct power parts to fit the engines size. Not looking for a all out engine.
So it seems that Jim wanted to get a bigger inch short block and use the rest of his package, w/o doing anything else other than maybe a intake and carb upgrade. Bad idea IMO.
BTW...bigger is definately not better in a small boat like your flatty. Big bore, short stroke combinations like Brian was talking about are readily "proven" combinations. Well, at least among those who aren't interested in "bragging" numbers, or who think for themselves.
I agree ... I think he was going after the #'s
Short rod
Pro:
» Provides very good intake and exhaust velocities at low to moderate engine speeds causing the engine to produce good low end torque, mostly due to the higher vacuum at the beginning of the intake cycle. The faster piston movement away from TDC of the intake stroke provides more displacement under the valve at every point of crank rotation, increasing vacuum. High intake velocities also create a more homogenous (uniform) air/fuel mixture within the combustion chamber. This will produce greater power output due to this effect.
» The increase in piston speed away from TDC on the power stroke causes the chamber volume to increase more rapidly than in a long-rod motor - this delays the point of maximum cylinder pressure for best effect with supercharger or turbo boost and/or nitrous oxide.
» Cam timing (especially intake valve closing) can be more radical than in a long-rod motor.
Con:
» Causes an increase in piston speed away from TDC which, at very high RPM, will out-run the flame front, causing a decrease in total cylinder pressure (Brake Mean Effective Pressure) at the end of the combustion cycle.
» Due to the reduced dwell time of the piston at TDC the piston will descend at a faster rate with a reduction in cylinder pressure and temperature as compared to a long-rod motor. This will reduce total combustion.
I think even with the con's ... the short stroke/short rod would best suit his needs ... 3.76" crank/6.135" rod/427 4.5" bore piston ... a VERY reliable pump gas motor ... with a great powerband ... great for a quick reving
in closing, let me say this. The most highly researched engine development program in any racing venue is, IMO, NHRA Pro Stock. The most successful Pro Stock motors out there are running a rod ratio in the area of 1:7:1. BIG bore, SHORT stroke, but with a rod ratio in that 1.7 range. Something to think about.
I was trying to get him "off the shelf" parts for a budget build from a proven package ... bus I agree with this last quote ... BIG BORE/SHORT STROKE
But like you said:
Ah, hell, Brian, WTF do we know?

[Carnivalride]

To continue this...
The ratio of the 396/427 and 454 is borderlline practical for the street, and only make good power because of their big intake ports.
Lets look at how rod length effects intake effeciency. An “n” value of 1.75 is considered “ideal” by some respected engine builders, if the breathing is optimized for the design. Except for purpose-built racing engines, most other projects are compromises where 1.75 may not produce the best results. There will be instances where the choice of stroke or rod has not been made, but the intake pieces (carburetor, manifold, and head) have been selected. Some discretion exists here for making the rod and/or stroke choice compatible with the existing intake. The “n” value can be used to compensate for less-than-perfect match of intake parts to motor size & speed. The reverse is also possible: the lower end is done, but there are still choices for the top end. Again, the “n” value can be used as a correction factor to better “match” the intake to the lower end.
So, IN GENERAL, we can summarize that engines with Low “n” numbers (short rods in relation to stroke, between 1.45 - 1.75) will tend to like large intake port volume vs. motor size, they'll perfer single-plane or 360° intake manifolds, large carburetor vs. engine size, moderate engine speed, and if we were talking cars, taller axle ratios. On the other hand, enginrs with higer "n" numbers (longer rods in relation to stroke, beteween 1.75-2.1) will be more compatible with small intake port volume vs. motor size, they'll like dual-plane 180° intake manifolds, small carburetors vs. engine size, and higher engine speeds. Again. if we were talking cars, we'd be talking lower axle ratios, as well.
I was also wondering about the rod angle info you posted. I was always told that the angle was figured with a crank at 90* ATDC. Are you getting your numbers at max thrust? (Rod at 90* to the journal...usually about 70-76 deg. crank rotation) To get the rod angle I'm familiar with, you use this formula: Stroke/ (rod length*2) = sin of rod angle. Then I just use a scientific calculator to get the angle. I think that anything above about 17* is asking for trouble, and is going to require a pretty strong rod and bolts. BB Chev. 396/427 is at 18*, and the 454 is 19*! There is a LOT of force on the major thrust surface of the piston in a BB Chev...one of the big draw backs of short rods. They need to be very strong w/ good bolts in any performance app. That's why the "big" dimple rods came w/ 7/16 Boron bolts. ONe of the reasons the 400 SBC was such a dog is due to it's 1.46 "n" and it's 20* rod angle. A 6" rod is a MUST for any performance 400 rebuild.
OK...I'm done with this for now...I hope this helps shed some light on why certain packages work the way they do. I know it was a long read, and there's a lot more info on the subject, but in closing, let me say this. The most highly researched engine development program in any racing venue is, IMO, NHRA Pro Stock. The most successful Pro Stock motors out there are running a rod ratio in the area of 1:7:1. BIG bore, SHORT stroke, but with a rod ratio in that 1.7 range. Something to think about.
Seems like my original thought wasn't too far off from this. :cool: :cool:
[QUOTE=Carnivalride]
Out of curiosity why did you recommend the 6.135” long rod for this 479cid deal? I looked at doing something similar to this and was going to use a 6.385” long rod and 1.520” wrist pin height pistons (stock rod 4.25 stroke) to save a little weight and cash (off the shelf pistons). If I figured right you would still have .012” to deck the block for a “zero” deck height. Do you not like changing the rod ratio from 1.629 to 1.695 or is there some other reason I didn’t consider? Just asking.
Loren
[QUOTE]
[QUOTE=steelcomp]
Sorry...couldn't resist. Gimme a break...I can't afford to use any of this stuff, so at least I can share it. Besides, you started it. LOL!!
[QUOTE=steelcomp]
Hey I ressemble that remark! :cry: :cry:

[fc-pilot]

Now I will screw everything up. The real problem is both theories have merit and can add power if the combo is built around these facts. The problem arises when they go with one of the theories and then can't tune the dang engine and comes back and tries to blame someone on the board because he did what "that one guy" said. I usually try not to get too deep with guys because half the time they are not ready to take it all in. (It took me twenty something years to take in what I know, and I am just starting to get a small grasp). I do have to say that I have enjoyed reading your posts. Thanks.
Paul

[Carnivalride]

Now I will screw everything up. The real problem is both theories have merit and can add power if the combo is built around these facts. The problem arises when they go with one of the theories and then can't tune the dang engine and comes back and tries to blame someone on the board because he did what "that one guy" said. I usually try not to get too deep with guys because half the time they are not ready to take it all in. (It took me twenty something years to take in what I know, and I am just starting to get a small grasp). I do have to say that I have enjoyed reading your posts. Thanks.
Paul
Paul,
Here's the deal as I see it. :) This is an open thread asking for information and ideas, most people (I believe) will try to give you what they consider "good" information. Now it's up to you to research this information and ideas to decide if YOU think its feasible.
IMO..... IT is my boat the ultimate decisions concerning, safety, performance and expenditures lies on ME not someone who posted (I hope others have this attitude as well). I am not paying for this information nor do I know the creditials of most of these forum participants. So I have to use my past experience and best judgment with this as well as any information I look at. Since I am financially challenged on my boat project I usually have way more time to read and research ideas than to ever test them.
Besides I said I had considered a combination similar to this, but my budget only allowed I rebuild using my best 454 block, crank and heads coupled with a few well thought out aftermarket peices. 479/492 requires an aftermarket or at least 502 block for about the same price I could put a set of aluminum heads on my 467. Which is better, I'll probably never know but I know I couldn't afford/justify either an aftermarket block and aluminum heads for my lake race/bracket boat.
I just enjoy hearing input from others especially when it was along the lines of something that I wanted to try.
Just my .02,
Loren

[steelcomp]

Well. Here's the thing about all this info...it's only a part of the equation AFA what makes an engine work, or why it works the way it does. I didn't intend to imply that one school of thought was better or worse than another, just providing "more data". Most of what I posted isn't supposition, it's basic engineering and physics, more to Brian's understanding than mine. I haven't had the opportunity to build countless engines on my own and come to my own conclusions, so I try and learn vicariously through other's efforts. What I posted here should have, somewhere in there, the disclaimer that these are general guidelines, and not written in stone. There are so many other factors in the way an engine performs that, change any one of them, and you're in a totally different ball game, playing with a new set of rules. That's why it's so important to identify, in as much detail as possible, what your intentions and specific goals are. The rod ratio issue has been pretty well flogged, and the general consensus is, that a ratio of 1.7 +/- is optimum. I didn't come up with that, but I know that it's used widely, by engine builders with much more experience and knowledge, and budgets to support their endeavors, than I'll ever have. BUT...a rod ratio of 1.7, by itself, isn't going to get you anywhere. For the BBChev configuration, (which includes the aftermarket industry), everything has been developed around it's 1.5-1.6 "n" configuration which, like was shown, does have it's advantages. Any advantage can be exploited, which is the goal with any engine, especially within the limitations of "available funds". Remember, GM didn't arbitrarily build motors with these characteristics, they had their reasons, and the dimensions of this engine combination were chosen very specifically by very smart engineers spending lots of GM's money. What I posted AFA the pro's and con's wasn't discovered yesterday...that's OLD stuff, and the engineers knew long ago the differences. I mean, lets face it, my little 467 dosen't seem to suffer too badly from an excessive rod angle, and short ratio, so there's some merit to their thinking. However, comma, the intake, heads, carburation, and especially the cam, all have been developed around that configuration. It's all in the combination and balance of parts that are intended and designed to work together. To just arbitrarily change one main part, like going to BIG cubes, without thinking how it's going to effect the overall package, is just wrong, and seldom generates the desired results. I'm just hoping that some or all of this info is usable to others for more understanding on how, and why, different configurations have the characteristics they do. :D
Busby, check your PM's.

[BUSBY]

yeah ... what scott said!
Oh sorry ...
Scott got it and replied ...
for everyone else ... as far as our merits/experience ... Scott's just a Contractor & I'm just a Broker ... so we don't know much ... just a couple of guys who've play with a couple of big blocks ...
well, maybe more than a couple :D

[BIGCHRIS]

Paul,
Here's the deal as I see it. :) This is an open thread asking for information and ideas, most people (I believe) will try to give you what they consider "good" information. Now it's up to you to research this information and ideas to decide if YOU think its feasible.
IMO..... IT is my boat the ultimate decisions concerning, safety, performance and expenditures lies on ME not someone who posted (I hope others have this attitude as well). I am not paying for this information nor do I know the creditials of most of these forum participants. So I have to use my past experience and best judgment with this as well as any information I look at. Since I am financially challenged on my boat project I usually have way more time to read and research ideas than to ever test them.
Besides I said I had considered a combination similar to this, but my budget only allowed I rebuild using my best 454 block, crank and heads coupled with a few well thought out aftermarket peices. 479/492 requires an aftermarket or at least 502 block for about the same price I could put a set of aluminum heads on my 467. Which is better, I'll probably never know but I know I couldn't afford/justify either an aftermarket block and aluminum heads for my lake race/bracket boat.
I just enjoy hearing input from others especially when it was along the lines of something that I wanted to try.
Just my .02,
Loren
Well said Loren i agree 100% :idea:

[steelcomp]

Well said Loren i agree 100% :idea:
Ditto...that was a good thought, Loren. :D

[Carnivalride]

Ditto...that was a good thought, Loren. :D
Thanks, Scott and Big Chris. :)

[Carnivalride]

Jim,
You have a PM.
Loren

[fc-pilot]

Well I did it, I rocked the boat. I did not mean to. What I was referring to was how some people get in over their head. I know a few engine builders that are driven nuts by their clients. I knew of one that we helped to screw up. He built an engine that was injected and his customer would come over and ask what we ran for tune-up stuff. Not thinking much we would tell them the pill, secondary shims, and timing. We did not find out till we talked with their engine builder that they were taking our info and putting it to their car. That was what I was talking about. Their builder put forty plus pulls on that motor trying different injector locations, timing, valve lash and more. They then refused to follow any of the tuning info that came with the motor. Those are the ones that I was joking about. I was not saying that the info given was bad (on the contrary, I found it quite good), it is just that some guys hear all these great tricks and build their engine around them, then don't know how to jet their carb. Anyway, sorry for the interruption, back to our regularly scheduled program...
Paul

[bigkatboat]

Loren, I still feel you are going in the correct direction. When you are ready to step up to a set of 'last year's pro stock heads', at about $5500.00, then you will be ready to spin that "pro stock 500" motor 10K rpms. Most big bore short stroke motors built today have 4 valves per cylinder. If only using 2 valves per cylinder, they have monster valves, and/or monster cam timing. With the breathing area of 4 valves, the builder can use a "mild cam timing" and create a 'easily tuned' package. However, 2 valve heads present a totally different direction in parts and 'tune up' combinations. Having built/ tuned carburated "River Racer" class motors using cams that lift .904" (1.8) intake, and .886" (1.7) X, I can tell you that the "crazy tune ups", wild rpm ranges, and material wear (read that valve springs), make the "Pro Stock" type motors very UN user friendly. Warren Johnson has plenty of time and money to "play" with these motors, my customers and I don't. By the way, you don't turn a BB Chevy over 8700 rpms (1/4 mile) with a wet sump! More $$$$$

[Carnivalride]

Loren, I still feel you are going in the correct direction. When you are ready to step up to a set of 'last year's pro stock heads', at about $5500.00, then you will be ready to spin that "pro stock 500" motor 10K rpms. Most big bore short stroke motors built today have 4 valves per cylinder. If only using 2 valves per cylinder, they have monster valves, and/or monster cam timing. With the breathing area of 4 valves, the builder can use a "mild cam timing" and create a 'easily tuned' package. However, 2 valve heads present a totally different direction in parts and 'tune up' combinations. Having built/ tuned carburated "River Racer" class motors using cams that lift .904" (1.8) intake, and .886" (1.7) X, I can tell you that the "crazy tune ups", wild rpm ranges, and material wear (read that valve springs), make the "Pro Stock" type motors very UN user friendly. Warren Johnson has plenty of time and money to "play" with these motors, my customers and I don't. By the way, you don't turn a BB Chevy over 8700 rpms (1/4 mile) with a wet sump! More $$$$$
George,
I understand some of the above, enough to know that high rpm is hard on parts and I can't afford it right now. But I do admit to the sickness of loving to hear naturally aspirated mills turn 9,000+ rpm! No I can't afford it and probably won't ever do it, but I still love the sound.
As far as my current deal, I think it will dial in where I want it if the weather will ever let me continue testing. This spring after I get some hard numbers with both props and both gear sets I'll cut one prop down an 1/8" to start with and retest, then maybe another 1/8" or a higher set of gears? Who knows right now it's snowing! :yuk: :yuk: :yuk:
Paul,
Don't worry about rocking the boat with me, it's all good. Now if I could only figure out how to jet my carb? :rolleyes: :D :D
Later,
Loren

[steelcomp]

Loren, I still feel you are going in the correct direction. When you are ready to step up to a set of 'last year's pro stock heads', at about $5500.00, then you will be ready to spin that "pro stock 500" motor 10K rpms. Most big bore short stroke motors built today have 4 valves per cylinder. If only using 2 valves per cylinder, they have monster valves, and/or monster cam timing. With the breathing area of 4 valves, the builder can use a "mild cam timing" and create a 'easily tuned' package. However, 2 valve heads present a totally different direction in parts and 'tune up' combinations. Having built/ tuned carburated "River Racer" class motors using cams that lift .904" (1.8) intake, and .886" (1.7) X, I can tell you that the "crazy tune ups", wild rpm ranges, and material wear (read that valve springs), make the "Pro Stock" type motors very UN user friendly. Warren Johnson has plenty of time and money to "play" with these motors, my customers and I don't. By the way, you don't turn a BB Chevy over 8700 rpms (1/4 mile) with a wet sump! More $$$$$It's always fun to see how threads morph from one subject to another. This thread started by someone asking about big inch stroker motors for a flat. Then it was suggested that he'd be better off staying with a shorter stroke, smaller displacement engine than what he was looking at, and now were talking about four valves per cyl., and 10K rpm "pro stock" motors. LOL!! :rolleyes:

[cstraub]

In a 4 stroke motor you want a long rod on the compression stroke so that you can take advantage of mechanical leverage. But in the suction stroke the longer rod let's the piston sit dead still at tdc for several crankdegrees and the incoming charge is blocked off under this period. The shorter rod will move the piston away from tdc quicker and will also accelerate the piston faster from tdc to about half way down the bore and that is creating a harder pull on the incoming charge and you will have better cylinder filling".
Just about everyone I know is brought up to believe this. The GM engineers believed it to until we proved it to be false. In 1995 reher Morrison conducted an R&D project funded by General Motors to once and for all prove the Rod ratio theories that everyone subscribes to. In a tall deck small block Chevy the rod ratio was changed from 5.550 to 6.650. The difference in ratio was 1.59 to 1.91. The difference in power? NOTHING, not one single horse power difference. The dyno sheets looked identical in every way all the way up to 9000rpm. That is why I now say its a fallacy.
This is a quote from Darin Morgan of Reher and Morrison. I thought is might be of interest to this post. . . .

[steelcomp]

In a 4 stroke motor you want a long rod on the compression stroke so that you can take advantage of mechanical leverage. But in the suction stroke the longer rod let's the piston sit dead still at tdc for several crankdegrees and the incoming charge is blocked off under this period. The shorter rod will move the piston away from tdc quicker and will also accelerate the piston faster from tdc to about half way down the bore and that is creating a harder pull on the incoming charge and you will have better cylinder filling".
Just about everyone I know is brought up to believe this. The GM engineers believed it to until we proved it to be false. In 1995 reher Morrison conducted an R&D project funded by General Motors to once and for all prove the Rod ratio theories that everyone subscribes to. In a tall deck small block Chevy the rod ratio was changed from 5.550 to 6.650. The difference in ratio was 1.59 to 1.91. The difference in power? NOTHING, not one single horse power difference. The dyno sheets looked identical in every way all the way up to 9000rpm. That is why I now say its a fallacy.
This is a quote from Darin Morgan of Reher and Morrison. I thought is might be of interest to this post. . . .
Hmmm. I can see so many holes in that it looks like a seive.
Tall deck SBC? I wonder if he means the Rocket block (Dart) or the Bow Tie...either, it dosen't mater.
The math dosen't work out on those numbers. I get two different strokes.
To JUST change a rod and expect to see any difference is bogus. I'm also skeptical of the claim of the same numbers "all the way to 9000". What on earth kind of "test motor" are they using that can rev 9000 rpm? I don't believe that you can change the rod ratio by that much and have it make no difference, unless the motor was so far out of tune that it didn't matter.
Running a 5.550 rod in a tall deck motor with 3.49" stroke would take a pretty tall, and heavy piston. (1.275 ch w/ 9.300 deck) Run that to 9000? Then just toss in another rod/piston combo and run 'er to 9000?
Sump'n don't smell right. :idea:

[BUSBY]

Well ... I guess that the engineering minds have taken over this thread ... myself included ... and experience prevails ...
Sorry JimW ... I was just trying to help with your budget build.
Brian

[Carnivalride]

Hmmm. I can see so many holes in that it looks like a seive.
Tall deck SBC? I wonder if he means the Rocket block (Dart) or the Bow Tie...either, it dosen't mater.
The math dosen't work out on those numbers. I get two different strokes.
To JUST change a rod and expect to see any difference is bogus. I'm also skeptical of the claim of the same numbers "all the way to 9000". What on earth kind of "test motor" are they using that can rev 9000 rpm? I don't believe that you can change the rod ratio by that much and have it make no difference, unless the motor was so far out of tune that it didn't matter.
Running a 5.550 rod in a tall deck motor with 3.49" stroke would take a pretty tall, and heavy piston. (1.275 ch w/ 9.300 deck) Run that to 9000? Then just toss in another rod/piston combo and run 'er to 9000?
Sump'n don't smell right. :idea:
Interesting. :idea: :idea: Like you said it seems like exact results would be very tough to get. We used to get over 1% difference on the diesel engines and they were the same just with production variences. If they used the same block it sure seems to me that a short rod piston would be heavier and have more area in contact with the cylinder wall unless they accounted for all that. :idea: :) :)

[steelcomp]

This is a quote from Darin Morgan of Reher and Morrison. I thought is might be of interest to this post. . . ."The dyno sheets looked identical in every way all the way up to 9000rpm. That is why I now say its a fallacy."
I wonder if he was building his own ($100K+ pro-stock) motor, he'd have that same attitude about con rod length. Build a motor, and just throw whetever rod in it that works. Doubtful.
Hey Chris (Straub)...what do the cup guys say about rod length?

[cstraub]

Scott,
The last Cup engine parts I saw from a top 10 team had rod/stroke ratio's of
1.94 to 1.88.
I found that on one of the other sites where the debate is going on so I thought I would post it. I will say what I have learned. I do quite a few 2 barrel cams a year. For years they went to long rods in these engines for the dwell. Well working with some of my customers we started playing with rod lengths based on the rules and track size. We ended up on some of the short tight 3/8" mile stuff with 5.565" rods in a 358 running a 4412. They would rocket off the corner and pull down straight quicker then the 6" and 6.25" stuff in the same car. I respect Darin's testing and if GM was footin' the bill then I'm sure it was complete. I will say this though, the engine that rpm's the quickest gets to its powerband faster, therefore it will win.

[steelcomp]

Thanks Chris. I think I've seen some Indy and F1 motors in the 2.0-2.2 range, which by our standards, is a short little rod, but a LOT of ratio. :D
Then there's this: A rod/piston out of a 900" John Kaase BB Ford, with a 6.35" (yes, 6.35) stroke. That's a 6.605" stock BB Ford rod next to it, for comparison.
http://popularhotrodding.com/tech/0512phr_big_16_s.jpg
I will say this though, the engine that rpm's the quickest gets to its powerband faster, therefore it will win.
Bingo!! All the HP and big numbers in the world won't do squat if the motor dosen't accelerate.

[BUSBY]

I will say this though, the engine that rpm's the quickest gets to its powerband faster, therefore it will win.
No matter which motorsport world one lives in ... this is the truest quote I have ever heard ...

[rmbuilder]

I wonder if he was building his own ($100K+ pro-stock) motor, he'd have that same attitude about con rod length. Build a motor, and just throw whetever rod in it that works. Doubtful.
Hey Chris (Straub)...what do the cup guys say about rod length?
A quote from David Reher (Reher Morrison)
"We also wanted to point out some of the common myths and misconceptions about high-performance motors. For example, I've seen dozens of magazine articles on supposedly "magic" connecting rod ratios. If you believe these stories, you would think that the ratio of the connecting rod length to the crankshaft stroke is vitally important to performance. Well, in my view, the most important thing about a connecting rod is whether or not the bolts are torqued!
If I had to make a list of the ten most important specifications in a racing engine, connecting rod length would rank about fiftieth. Back in the days when Buddy Morrison and I built dozens of small-block Modified motors, we earnestly believed that an engine needed a 1.9:1 rod/stroke ratio. Today every Pro Stock team uses blocks with super-short deck heights, and we couldn't care less about the rod ratio. A short deck height improves the alignment between the intake manifold runners and the cylinder head intake ports, and helps to stabilize the valvetrain. These are much more important considerations than the rod-to-stroke ratio. There's no magic - a rod's function is to connect the piston to the crankshaft. Period."

[cstraub]

Bob's batting clean-up. Thanks thats great.

[cstraub]

No matter which motorsport world one lives in ... this is the truest quote I have ever heard ...
Busby,
yeah and if most would step back and take a moment to learn this then we wouldn't sterotype an engine builder as a circle track guy, a drag race engine builder, a marine engine builder.. . at PRI Allen and Todd Patterson were at the booth, neat people and good friends with the boss, and they are going to build some road race engines. . .I smarted off the Allen "you can't do that you build drag engines". He just smiled. Hell boys its just different parts, diferent tolerances,but the same goal.
Busby I can't remember who told me that years ago but I think it was John Reed of Reed Cams.

[steelcomp]

Busby I can't remember who told me that years ago but I think it was John Reed of Reed Cams.
I learned it from The Old One. I'm gonna start another thread. Watch this. :argue: :) :p

[steelcomp]

A quote from David Reher (Reher Morrison)
"We also wanted to point out some of the common myths and misconceptions about high-performance motors. For example, I've seen dozens of magazine articles on supposedly "magic" connecting rod ratios. If you believe these stories, you would think that the ratio of the connecting rod length to the crankshaft stroke is vitally important to performance. Well, in my view, the most important thing about a connecting rod is whether or not the bolts are torqued!
If I had to make a list of the ten most important specifications in a racing engine, connecting rod length would rank about fiftieth. Back in the days when Buddy Morrison and I built dozens of small-block Modified motors, we earnestly believed that an engine needed a 1.9:1 rod/stroke ratio. Today every Pro Stock team uses blocks with super-short deck heights, and we couldn't care less about the rod ratio. A short deck height improves the alignment between the intake manifold runners and the cylinder head intake ports, and helps to stabilize the valvetrain. These are much more important considerations than the rod-to-stroke ratio. There's no magic - a rod's function is to connect the piston to the crankshaft. Period."
It's about this time I suspect that there's a TON of difference in rod ratio. IMO, there isn't an engine development program out there, in any form of motorsport, that does the level of R&D, and protects it's secrets, as much as NHRA Pro Stock. Disagree with that if you want, but I'll stand by that statement. So for anyone as deeply involved in Pro Stock development as Dave Rehr, or Budy Morrison, to come out and make a claim like that, I'm gonna think exactly the opposite.
Now, to say you can make the same amount of power with any reasonable rod ratio, I'll buy that, but with each different ratio there's going to be different design paramaters. Like I said earlier, each (long vs. short) has their advantages and disadvantges. Here's anexample.
Chris, why do you need to know rod length when designing a cam? Is the lobe going to be the same for a rod ratio of 1.56 as it is for a ratio of 1.75? Everything else being the same in the motor?

[BUSBY]

Here's anexample.
Chris, why do you need to know rod length when designing a cam? Is the lobe going to be the same for a rod ratio of 1.56 as it is for a ratio of 1.75? Everything else being the same in the motor?
Awe Scott ... why'd you have to go there?
Now you've dusted off a whole different section of my brain! I'm getting prepped to go to Rio and you're gonna have me thinking about this for 2 whole weeks before I cam come back and revisit this? Now is when this thread is getting good! Damn it!
See what happens? I get ready for a good vacation and all of the good stuff starts to come out ...
Well JimW ... get your pencil out ... if you want to know why you should or shouldn't do something, you've got it if this continues ... (hopefully it will from an educational standpoint) ...
Thanks Scott ... :cry:

[steelcomp]

Awe Scott ... why'd you have to go there?
Now you've dusted off a whole different section of my brain! I'm getting prepped to go to Rio and you're gonna have me thinking about this for 2 whole weeks before I cam come back and revisit this? Now is when this thread is getting good! Damn it!
See what happens? I get ready for a good vacation and all of the good stuff starts to come out ...
Well JimW ... get your pencil out ... if you want to know why you should or shouldn't do something, you've got it if this continues ... (hopefully it will from an educational standpoint) ...
Thanks Scott ... :cry:
That's what you get for bogartin' on Willis' thread. :yuk: :D
If I know you, you'll have your laptop...you won't miss much. (between hangovers) LOL :p :rolleyes: :D

[BUSBY]

That's what you get for bogartin' on Willis' thread. :yuk: :D
If I know you, you'll have your laptop...you won't miss much. (between hangovers) LOL :p :rolleyes: :D
I do have the lap top and check in from every now & then to see what's up ... but sometimes I have to tell myself to "step away from the computer" ... :220v:

[cstraub]

Chris, why do you need to know rod length when designing a cam? Is the lobe going to be the same for a rod ratio of 1.56 as it is for a ratio of 1.75? Everything else being the same in the motor?
No the cam is different. Rod length plays a part in determing where the tappet position needs to be throughout the "lift path" of the lobe.
Chris
We can get into this but as Busby said I to am getting ready to battle the airports tonight. . .but hell I am flying into "Hotlanta" for a connection so I may have plenty of time at Delta's hub...if not we will continue next week when it is dead.

[BUSBY]

No the cam is different. Rod length plays a part in determing where the tappet position needs to be throughout the "lift path" of the lobe.
Chris
We can get into this but as Busby said I to am getting ready to battle the airports tonight. . .but hell I am flying into "Hotlanta" for a connection so I may have plenty of time at Delta's hub...if not we will continue next week when it is dead.
Yeah but I'm gonna be gone until the 7th of Janurary! Oh Well ... you have a Merry X-Mas!