Big-Block Chevy Marine Performance Book

[kevnmcd]

Anyone have one that they aren't using anymore? I have tried to find it eveywhere and no one has one....eveyone is out of stock! :cry: If anyone has one or knows where to find one, please let me know. Thanks.

[Beer-30]

That's a pretty old book. I don't think too much would apply to todays equipment.
As far as equipment and building a big-block goes, there is a ton of info right here.
Personally, I have never read that book. I have an older big-block non-marine book. Not much applies today.

[kevnmcd]

I am pulling my motor this winter to do some upgrades. I will be going with a bigger cam and I understand that this book has some very good suggestions on this.

[Beer-30]

Ah. Let me think. I believe Bob Teague gave a recommendation for your very thing. Let me see if I can find it.

[cstraub]

Set a goal, ie speed. Set a budget. Then post up here in the tech section. Believe me there is some good knowledge on this board.
Chris

[Beer-30]

Here's an exerp from Powerboat Mags tech section.
I know your's isn't an HP, but it is still a 502
It's not the exact one I am thinking of, but it looked good:
502 HEAD, CAM COMBINATION GAME
QUESTION: I have a 1999 carbureted HP500 that is stock except for a rectangular port Edelbrock RPM "air gap" intake manifold and CMI E-Top exhaust. I can attain 5,300 rpm in my Scarab 22. As the engine goes through a rebuild, I would like to improve its performance. I am looking for aluminum heads and a good matching cam that will work with my intake manifold and desired rpm level. I've asked four different engine builders, and I get four different answers—and not direct answers, either. Is this subject top secret? I like the Air Flow Research 305 with 114 cc chambers, but with the exhaust ports .300- inch higher, will this throw off my tailpipe alignment? How about the Edelbrock heads? And then, what cam should I use? Let the combination games begin.
Jeff Boyer
Stoddard, Wis.
ANSWER: Aluminum heads are becoming more popular these days with the types of fuels that are available. Lately, I have seen a rash of iron heads (especially Generation V and VI GM heads) having problems with exhaust seats falling out or disintegrating. One of the theories is that using gasoline with methanol or fuel that is oxygenated is resulting in higher combustion temperatures, which could be causing the exhaust seats to loosen or fail. If you intend to reuse your stock heads, it is highly recommended that new exhaust seats are installed with a tighter press fit than stock.
Aluminum heads that are an exact design of an iron head will not produce more horsepower because of the material change alone. The truth is, all things being equal, iron heads can produce more power because they hold the combustion heat more readily. On the other hand, aluminum heads, because of their ability to dissipate heat, provide for greater reliability and more insurance against detonation. The good news is that there are many aluminum heads now available that are superior in design to your stock GM heads. These designs more than offset the power difference resulting from the difference in materials.
There are two main things to consider when selecting a head for your naturally aspirated motor: the runner volume and the chamber volume. The intake runner volume will affect the velocity in the intake runners. If the volume is too large for the engine size, drivability and low-end torque could be negatively impacted. The chamber volume will affect the compression ratio when used in combination with a given piston design.
Most aftermarket heads are designed to bolt on a 454-cubic-inch engine that has a 4.250-inch bore. Your engine now has a 4.467-inch bore and likely will have a 4.500-inch bore when you get done rebuilding it. The AFR with the 114 cc chambers, and the Edelbrock head with the smaller chambers are intended in part to bolt on an otherwise stock 454 with the result being a mild increase in compression ratio. The problem is that when the smaller diameter chamber (which is designed to match a 4.250-inch bore) is used in combination with the larger bore, part of the head deck surface is left hanging into the bore. It is more desirable to have the diameter of the chamber on the spark plug side pretty much match the diameter of the cylinder bore.
If you intend to raise the compression a little, and you are in the process of rebuilding the engine, I would opt to change the pistons to a design that has a little "pop-up" to displace some of the volume at top dead center. This way, you can use a head with a chamber that is "laid out" to the bore size and still increase the compression ratio a little. The Air Flow Research head with the 305 cc runner is a good choice. I think I would go with the AFR CNC ported 335 design for your application. Other good choices would include the Edelbrock marine head and the Brodix BB-2Plus. In any case, it is mandatory that you use extreme-duty and Inconel valves.
With your CMI E-Tops, there is little worry about water reversion. This will allow you to use a little more aggressive cam profile than would have been possible with the stock GIL system. The current camshaft in your engine is a Crane hydraulic roller that is on the small side. I would step it up a few notches to either a Crane 139741 (for Gen V engines) or the 168741 (for Gen VI engines). Use the Crane 13532 lifters with the tiebar design in either generation engine. The tiebar design works better to keep the lifters in line compared with the OEM generation VI configuration.
If the heads you choose have longer-than- stock valves, you will have to increase your pushrod length accordingly. For the hydraulic roller setup, your valve springs should provide about 150 pounds of pressure on the seat and about 450 pounds over the nose. A good (and not too expensive) spring that works well is the Comp Cams 929, which installs at 1.880-inch to achieve the desired seat pressure. If you want to use one of the best springs available, opt for the Isky Part No. 9905, which is a PSI spring assembly with a dampener. The Isky spring installs at about 1.940-inch to achieve the desired seat pressure.
If you do all this work, I would consider changing the ignition to an MSD setup, which will allow you to raise the rev-limiter a few hundred rpm. The recommended hydraulic roller setup, with a little increase in compression, in combination with your CMI exhaust, and the right carburetor will have no problem going to 5,800 rpm or so.

[BUSBY]

Well ... according to Penguin Putnam, the parent company of the publisher ... that book was released in 1998 and in no longer in print as of 2002 ...
So it looks like you'll need to find a pre-owned one or one at a book store from an original stock order. You might find one at a local HP swapmeet, they usually have a few book vendors.
I asked if they had a list of large orders purchased by stores ... they said WalMart was the largest orderer ... so it looks like that is your best bet.
Good Luck,
Brian

[Beer-30]

Oh, not as old as I though. My bad. Sorry.
Here is another little spit from Crane Cams:
We offer cams for both the marine Gen 6 big block Chevy (454-502) and the 8.1L big block Chevy. You can also use the 8.1L Crane hydraulic roller tappet, Part No. 26535-16, in both engines, but you cannot use the Gen 6 hydraulic roller tappet, Part No. 16535-16, in the 8.1 engine because the oil gallery location is different and you will lose oil pressure.
Interestingly, the camshaft in all Mercury Marine’s 400HP, 420HP, 425HP and 525SC is the same cam, Crane Part No. 132561.
The Crane cams used in the Mercury Marine 525HP carbureted engine are different from the 525HP EFI engine. The 525HP carbureted engine uses Crane Cams Part No. 169621 and the 525HP EFI engine uses Crane Part No. 16HR00004.
You can change your G.M. Marine GEN 6 engine to adjustable rocker arms by using Crane Part No. 99152-16 studs and No. 13750-16 rocker arms. This is a fairly simple, bolt-on installation!

[BUSBY]

Set a goal, ie speed. Set a budget. Then post up here in the tech section. Believe me there is some good knowledge on this board.
Chris
After watching Scott's (steelcomp's) rebuild ... it looks as if you are a good source for cam ideas ... :D

[kevnmcd]

Well, since everyone is being so helpful, here is the scoop.
The motor is a stock 1995 502 EFI (Gen V). I am looking to get another +/- 100 hp out of it. I will be adding Dana exhaust to it and getting rid of the stock fuel delivery system. The new fuel delivery system will be an aftermarket electric fuel pump, fuel rail coolers, and an adjustable fuel pressure regulator.
What I am trying to figure out right now is
1) what the stock cam specs are
2) what the new cam specs should be to get me the increase in hp
I will take any suggestion you guys have. Fire away! :rollside:
edit: I will also be putting larger valves in the heads: 2.25intake/1.89exhaust

[kevnmcd]

Thanks for the info Beer-30! That was some good stuff.

[kevnmcd]

I asked if they had a list of large orders purchased by stores ... they said WalMart was the largest orderer ... so it looks like that is your best bet.
Good Luck,
Brian
Brian - Tried them....they are out! :(

[Beer-30]

:D You be welcome.
Heads, cam and exhaust should get you there.
Tyler Crockett had a 100-110 HP bolt on head, cam kit. I am sure he still does. Uses your heads or swaps you for another pair. Kinda like the Raylar kit for 496s, except Tyler sticks with iron heads. Alum would get you probably just a few more HP, but also a weight savings. Edelbrock has a nice bolt-on pair that I was looking at before I ended up with a 496.
Edelbrock heads: (directly from their site)
http://www.edelbrock.com/automotive_new/mc/heads/images/60459.jpg
MARINE-DUTY PERFORMER RPM 454-O AND 454-R
Heavy-duty, 1.89" Inconel exhaust valves provide added durability for marine applications
Hard anodized to protect the aluminum in the harsh marine environment
Sold with valves only to allow for valve spring choices
Match with an Edelbrock Performer RPM manifold, Performer Series 750 cfm marine carb and Performer RPM cam for proven performance
Smaller-than-stock 11/32" valve stems promote excellent flow and lighter valve weight
PERFORMER RPM 454-O MARINE OVAL PORT
Chamber Size Intake Port Size Valve Sizes (in/ex) Bare (single) Complete (single)
110cc 290cc 2.25"/1.89" N/A #61459*
PERFORMER RPM 454-R MARINE RECTANGULAR PORT
118cc 315/300cc (long/short) 2.25"/1.89" N/A #61559*

[Beer-30]

And here is what Tyler Crockett Marine Engines does. It is their +100HP kit:
From their site:
454 & 502 MPI EFI Update
PARTS
Billet Flame Arrester
Adjustable Fuel Pressure Regulator
Custom Hydraulic Roller Camshaft
One Piece Pushrods
Rocker Studs
Roller Rocker Arms
Hex-a-just Timing Chain Set
2.250 Severe Duty Intake Valves
1.890 Inconel Exhaust Valves
Valve Springs, Retainers, Locks & Seals
Complete Stainless Exhaust System
Gasket Set
Fuel Pump & Fuel Cooler
Earls Hose & Fittings to Plumb Fuel System
Price - $4200.00
MACHINE WORK
Clean & Magnaflux heads
Install Bronze Liners
Valve Job Heads
Open Valve Seats for Larger Valves
Mill Heads .020
Cut Guides for Valve Seals
Check Installed Spring Heights
Assemble Heads
Price - $600.00
LABOR
Installation Of Kit on Engine - $1200.00
Dyno Engine - $500.00 plus fuel per day
Reprogram ECU - $350.00
This Price Quote is for Engine only does not include R&R

[kevnmcd]

I will be sticking with my original cast iron heads in hopes of saving a few $$$. Tyler Crockett's upgrade kit is exactly what I am looking at. I am trying to get a hold of him to find out what the specs are on the cam he lists in the kit....see here. (http://www.crockettmarineengines.com/products.html) According to the site, he shaves off .020 from the heads and adds the larger valves. He says with this kit he is seeing +/- 505 hp. I am sure I can bump this up a little with a little more compression. :rollside:

[kevnmcd]

Beer-30.....you beat me to it! :)

[Beer-30]

I was looking at two boats with 502s. I did a lot of research on them / as to what upgrades were available.

[kevnmcd]

I was looking at two boats with 502s. I did a lot of research on them / as to what upgrades were available.
If you have the time, I wouldn't mind any other info you found on upgrades. Want to make sure I have all my facts when I get into this project.

[Beer-30]

Sure thing. It'll be sporatic, I'll have to recall all of it.

[ralphspa]

I just purchased one on ebay , should be getting it next week.If you want i might be able to make you a copy if you still need it.

[Beer-30]

The cam Teague recommended to another guy was the Crane 139351. It has nice looking specs for your application, EFI and all.
I don't know if Crockett gives out the specs on the cam he uses.
Infomaniac may chime in here. I don't know him personally, but I can tell he is a top-notch engine builder with tons of knowledge. He is tight with Comp Cams, which is another brand I am fond of. He may know of a cam for your app.

[paradigm shift]

Set a goal, ie speed. Set a budget. Then post up here in the tech section. Believe me there is some good knowledge on this board.
Chris
Very good advice in this statement. If you are staying with the EFI I would stick with a proven package or plan on running on the dyno and someone that can tweak MEFI computer you have. Just my .02
cstraub69 - one of these days I am going to have you help with a head - cam combo on a build up. Another thread another time. :D

[VanDeano]

I have a couple left that are new. $29 includes shipping. I live in Torrance, not to far from you. Our you can find them under mercruiser on E-Bay. I only have a few left.
Dean

[Havasu Hangin']

I have one I can "rent" to you...
:D

[bigkatboat]

Teague had listed a few Crane cams in the past, 17048, 139741, and 169741. I could not find them on the Crane web site, am I in the wrong place? Just wanted to see what they had.

[Beer-30]

Teague had listed a few Crane cams in the past, 17048, 139741, and 169741. I could not find them on the Crane web site, am I in the wrong place? Just wanted to see what they had.
Hey, here you are again.
I think they may be Merc-Specific cams and may not show up. I saw the tech article where he suggests these. Like you I couldn't get a hit on them. Hmmmmmm.

[Beer-30]

Oh, and you would be needing this stuff too. Mainly the adjustable fuel regulator for the added HP. Hence, I had this scoped out, too:
http://store1.yimg.com/I/azspeed_1863_5650353
Arizona Speed and Marine has a great kit to squeeze 25-30 horsepower out of your 454 Magnum, 502 EFI, 502 Magnum, or HP500 EFI.
Re-calibration of your ecu precisely controls spark, fuel, idle speed and rev-limit.
Show quality polished billet flame arrestor increases airflow.
MSD 6M2 multiple spark ignition box for better idle and hotter spark
MSD jumper harness for easy electrical connection
Adjustable fuel pressure regulator kit
Super Tune Kit$995.00
As well as this:
http://store1.yimg.com/I/azspeed_1862_4694699
**Available on exchange basis**
Arizona Speed and Marine’s “Short Runner” Extrude Honed intake manifold is essential when extracting the most HP and Torque out of your MPI or Magnum EFI engine. First, the manifolds are precision CNC machined to unshroud the intake runners and shape the inlet. The manifolds are then Extrude Honed to further increase airflow. The reduction in overall runner length increases the HP and Torque operating range. These manifolds are available on an exchange basis.

[ECeptor]

I have a couple left that are new. $29 includes shipping. I live in Torrance, not to far from you. Our you can find them under mercruiser on E-Bay. I only have a few left.
Dean
Myself (and a bunch of others from OSO) recently bought copies from Dean. He quickly sent a brand new copy to me which I have read cover-to-cover since.
It's a great book and well worth the $29. The information you will learn from it will pay back many, many times over!

[cstraub]

Well, since everyone is being so helpful, here is the scoop.
The motor is a stock 1995 502 EFI (Gen V). I am looking to get another +/- 100 hp out of it. I will be adding Dana exhaust to it and getting rid of the stock fuel delivery system. The new fuel delivery system will be an aftermarket electric fuel pump, fuel rail coolers, and an adjustable fuel pressure regulator.
What I am trying to figure out right now is
1) what the stock cam specs are
2) what the new cam specs should be to get me the increase in hp
I will take any suggestion you guys have. Fire away! :rollside:
edit: I will also be putting larger valves in the heads: 2.25intake/1.89exhaust
Okay our goal is 100HP, now what is our Budget?
Chris

[kevnmcd]

Okay our goal is 100HP, now what is our Budget?
Chris
Total rebuild costs = $5,000 (excludes new exhaust)
That price is for parts and machine work only. I will be providing the labor which will included R&R of the motor.

[Beer-30]

Total rebuild costs = $5,000 (excludes new exhaust)
That price is for parts and machine work only. I will be providing the labor which will included R&R of the motor.
You're kidding, right? That would be a stock rebuild only. Freshening up what you have. No trick parts there, my friend.
To throw exhaust into the mix, $5K would be the headwork, new valvetrain, and the exhaust. It wouldn't quite touch the bottom end.

[GUGS102]

Shifity,
I was in your shoes a few months ago, I posted the following and was happy with the results and ultimately thrilled with the combination. If you want/need moreinfo on what I put together, shoot me a PM. I running it in a 78 hallet 19 ft. JG pump AA etc.
http://www2.***boat.com/forums/showthread.php?t=83751&referrerid=11757 (http://)
Thanks,
GUGs

[kevnmcd]

You're kidding, right? That would be a stock rebuild only. Freshening up what you have. No trick parts there, my friend.
To throw exhaust into the mix, $5K would be the headwork, new valvetrain, and the exhaust. It wouldn't quite touch the bottom end.
Maybe you misread my post. The $5k did NOT include exhaust. I will be doing all the work myself with the exception of machine work and the bottom end will be just a refresh, nothing more.
Unless I am mistaken, I don't know why is should cost more than that. Anyone else feel like I am off base here? :rolleyes:

[Beer-30]

Maybe you misread my post. The $5k did NOT include exhaust. I will be doing all the work myself with the exception of machine work and the bottom end will be just a refresh, nothing more.
Unless I am mistaken, I don't know why is should cost more than that. Anyone else feel like I am off base here? :rolleyes:
Ah, I did misread.
I still say it will be close. Look at Crockett's set-up, it is 4200 in parts, mainly. And that is cam and head (valvetrain). Nothing about pistons, rings, bearings, etc. That's what I was gauging by. :mix:

[kevnmcd]

Ah, I did misread.
I still say it will be close. Look at Crockett's set-up, it is 4200 in parts, mainly. And that is cam and head (valvetrain). Nothing about pistons, rings, bearings, etc. That's what I was gauging by. :mix:
You are correct about Crockett's list. But that price includes exhaust. I am going to go with Dana Marine instead of the Stainless Marine that he has included in that price. I think I should be close to that price. We shall see.

[Beer-30]

On the heads, you may be $ for $ with the Edelbrocks. Summit has them for 750/ea. Now, this includes valves (inconel), but not springs, locks, retainers. Seals are installed. By the time you clean, surface, cut bigger valves, install new seats, guides, screw-in studs, AND buy the valves, you would probably be right there. The lighter weight = more speed. The springs, retainers and locks are available in kit form along with new cam/lifters and it would all be matched, either Crane, Comp, or whoever.
I know Infomaniac can get you incredible pricing on CompCams, if you are not brand specific. I am sure he could save you a few hundred easy on the valvetrain - if he is still willing to do such things.
And whenever I touch my exhaust, it will be a set of red Lightnings. I gotta have a pair of these:
http://www2.***boat.com/image_center/data/500/2433headers.jpg

[cstraub]

Is this what you want:
502cid - 100% stock short block other than min. deck cut to make flat
8.8 compression. Did not zero deck - pistons .012" down + .040" headgasket
850 Sea Demon 82P 90S
HVH 1" Super Sucker
HV/Brodix 2000 Intake
Canfield 310 heads / CNC Chamber / No Port Work
Cam - custom Hyd Roller Just under 225 at .050 I w/112LSA
2" Primary Schoenfield Headers - dyno mufflers
Will test Gill Exhaust again when done testing in this state
Belt driven Sea Water pump working - cross over - alternator working - no PS pump.
89 octane fuel - yep, Winter Blend right from the gas pump.
35 Degrees total timing - HEI external coil distributor ( yes, the computer one) with Jacobs amplifier/coil
RPM HP Torque
2100 194.3 483.8
2200 206.6 495.67
2300 217.5 498.52
2400 231.0 505.70
2500 243.9 512.60
2600 256.8 519.00
2700 269.2 523.36
2800 279.9 524.64
2900 288.2 521.78
3000 295.2 516.70
3100 302.8 513.17
3200 312.2 512.08
3300 323.2 514.40
3400 336.7 519.97
3500 351.9 527.69
3600 374.4 542.69
3700 387.9 550.14
3800 406.6 562.41
3900 424.7 572.21
4000 440.7 578.35
4100 457.4 584.13
4200 468.2 586.44
4300 480.3 586.50
4400 490.9 585.93
4500 500.4 583.75
4600 508.8 580.29
4700 515.1 576.90
4800 526.3 575.77
4900 531.4 569.77
5000 536.0 563.20
5100 540.2 556.26
5200 540.9 546.34
This thing idles, it is "wife/girlfriend friendly" when backing off the trailer. Note this is with 89 octane and with accessories. The cam is EFI safe no problem.
Chris

[Beer-30]

3800 406.6 562.41
3900 424.7 572.21
4000 440.7 578.35
4100 457.4 584.13
4200 468.2 586.44
4300 480.3 586.50
4400 490.9 585.93
4500 500.4 583.75
4600 508.8 580.29
4700 515.1 576.90
4800 526.3 575.77
4900 531.4 569.77
5000 536.0 563.20
5100 540.2 556.26
5200 540.9 546.34
This thing idles, it is "wife/girlfriend friendly" when backing off the trailer. Note this is with 89 octane and with accessories. The cam is EFI safe no problem.
Chris
Nice!
That shows that it's all in the heads and cam, doesn't it?
Nice build.

[kevnmcd]

Chris,
The hp was still climbing. What happened? Did the rev limiter kick in at 5200? That cam sounds like it would work great with what I am trying to do.
Beer-30,
That is exactly what I am trying to do....work with the cam and heads only. :mix:

[cstraub]

Chris,
The hp was still climbing. What happened? Did the rev limiter kick in at 5200? That cam sounds like it would work great with what I am trying to do.
Beer-30,
That is exactly what I am trying to do....work with the cam and heads only. :mix:
This build was for the guy wanting "Blue Motor" power but not the "Blue Motor" price tag. The engine actually made 542 at 5300 but my customers goal was met and after 5300 it started to fall off. So he accomplished his goal.
Combination is key.
Chris

[kevnmcd]

OK, Chris - My goal is at least 500 hp at 5400 rpm's (that is where my rev limiter kicks in). I will be using my existing heads but installing larger valves (2.25 intake/1.89 exhaust). I will be using the same EFI setup that is currently on the motor. Would like to keep the compression as low as possible to utilize lower octane fuel. I want an engine that will idle at 600-700 rpms while in gear.
1) What compression should I go with?
2) What cam specs do I need to have?

[Beer-30]

So, hopefully just polish the crank, align bore the caps. Deck and square the block. Hopefully re-use the forged pistons. Square up the rods, re-balance bottom end.
I still would really see what the heads are going to cost you to re-do. Aluminums have come down since their evolution. I don't think Canfields are in your price range, but you may be able to get into the Edelbrocks or maybe the new TrickFlows.
If you can save some serious dollars with your heads and via a local head guy, I would highly suggest the ASM ported intake and match it to the heads. You will need every bit you can on the intake, as it would become your restriction point.
9:1 would be tops with Iron heads. To be safe.
The cam will be tough, as there are many many choices.
I would say something split pattern with 112-114 angle.

[cstraub]

OK, Chris - My goal is at least 500 hp at 5400 rpm's (that is where my rev limiter kicks in). I will be using my existing heads but installing larger valves (2.25 intake/1.89 exhaust). I will be using the same EFI setup that is currently on the motor. Would like to keep the compression as low as possible to utilize lower octane fuel. I want an engine that will idle at 600-700 rpms while in gear.
1) What compression should I go with?
2) What cam specs do I need to have?
1 No more then 8.8 to 1 with iron heads and 89 octane.
2 All depends on what the heads flow. Stock numbers on the 188's aren't bad but aren't all that great. So my guess on camshaft is as good as a 4 year old with a dart and a page of cams thumbnailed to a wall if we don't know what your heads flow. Now better then that would be to bolt that EFI ram intake on the head and flow it with that on it. Now we would be gettin' somewhere.
Air is your friend. The more air a head flows the less we have to lift and open time of the valve (lift and duration). So better flow less cam. Less cam in a boat means better idle, easier shifting, and most of all more useable power.
Can you get there with what you have, yes, but it will take some port work on the heads and even with that an ECU calibration. Now once this sickness called "need for speed" starts its hard to get rid of. Purchasing a set of aluminum heads may be a good start for a 540 CID down the road.
Chris

[Beer-30]

And, if you have to bore and go pistons, 514 (.060) is a better number than 502 :smile:
At that point, you might just want to go 7-800 higher and get a brand-new 502/502 Aluminum head long block and throw your injection on it. :devil:

[kevnmcd]

1 No more then 8.8 to 1 with iron heads and 89 octane.
2 All depends on what the heads flow. Stock numbers on the 188's aren't bad but aren't all that great. So my guess on camshaft is as good as a 4 year old with a dart and a page of cams thumbnailed to a wall if we don't know what your heads flow. Now better then that would be to bolt that EFI ram intake on the head and flow it with that on it. Now we would be gettin' somewhere.
Air is your friend. The more air a head flows the less we have to lift and open time of the valve (lift and duration). So better flow less cam. Less cam in a boat means better idle, easier shifting, and most of all more useable power.
Can you get there with what you have, yes, but it will take some port work on the heads and even with that an ECU calibration. Now once this sickness called "need for speed" starts its hard to get rid of. Purchasing a set of aluminum heads may be a good start for a 540 CID down the road.
Chris
With iron heads...what would my max c/r be with 91 octane?
I use this boat in salt water and heard that the iron heads will withstand this environment better than aluminum ones will. As for flow testing this setup, I will have to wait till I pull it out next month.

[cstraub]

OK, Chris - My goal is at least 500 hp at 5400 rpm's (that is where my rev limiter kicks in). I will be using my existing heads but installing larger valves (2.25 intake/1.89 exhaust). I will be using the same EFI setup that is currently on the motor. Would like to keep the compression as low as possible to utilize lower octane fuel. I want an engine that will idle at 600-700 rpms while in gear.
1) What compression should I go with?
2) What cam specs do I need to have?
1 No more then 8.8 to 1 with iron heads and 89 octane.
2 All depends on what the heads flow. Stock numbers on the 188's aren't bad but aren't all that great. So my guess on camshaft is as good as a 4 year old with a dart and a page of cams thumbnailed to a wall if we don't know what your heads flow. Now better then that would be to bolt that EFI ram intake on the head and flow it with that on it. Now we would be gettin' somewhere.
Air is your friend. The more air a head flows the less we have to lift and open time of the valve (lift and duration). So better flow less cam. Less cam in a boat means better idle, easier shifting, and most of all more useable power.
Can you get there with what you have, yes, but it will take some port work on the heads and even with that an ECU calibration. Now once this sickness called "need for speed" starts its hard to get rid of. Purchasing a set of aluminum heads may be a good start for a 540 CID down the road.
Chris

[kevnmcd]

And, if you have to bore and go pistons, 514 (.060) is a better number than 502 :smile:
For that matter, 509 (.030 over) is a better number than 502. :wink:

[Beer-30]

For that matter, 509 (.030 over) is a better number than 502. :wink:
Very true, but my theory was along the lines of no substitue for cubes. I know 502 blocks are plenty thick, but .060 is really safe. Still leaves .090 or .125 for later. You will pay the same for the boring, and for the pistons, so you might as well take the extra cubes if you are buying pistons. It will help you realize your HP increase even easier. ;)

[cstraub]

With iron heads...what would my max c/r be with 91 octane?
I use this boat in salt water and heard that the iron heads will withstand this environment better than aluminum ones will. As for flow testing this setup, I will have to wait till I pull it out next month.
Aluminum heads with hard anodizing work fine in salt water. Actually an anodized head will last longer then a cast iron head with open cooling. Salt will eat the cast iron eventually.
I would not go over 9 to 1 with 91 octane. An at that I would be sure the quench area is around a .035" to .040" to deturre detonation.
Chris

[kevnmcd]

Very true, but my theory was along the lines of no substitue for cubes. I know 502 blocks are plenty thick, but .060 is really safe. Still leaves .090 or .125 for later. You will pay the same for the boring, and for the pistons, so you might as well take the extra cubes if you are buying pistons. It will help you realize your HP increase even easier. ;)
Very true!

[kevnmcd]

Aluminum heads with hard anodizing work fine in salt water. Actually an anodized head will last longer then a cast iron head with open cooling. Salt will eat the cast iron eventually.
I would not go over 9 to 1 with 91 octane. An at that I would be sure the quench area is around a .035" to .040" to deturre detonation.
Chris
Thanks for all the info, Chris.

[cstraub]

Your welcome.
Just a note about cubes. I am a huge fan of cubes but boring a block out to get 10 more cubes doesn't really gain you anything. Lets look at it this way the best Cup engines make around 830HP out of 358CID. Thats 2.32~ HP per cube. So if you go from 502 to a 509 at best you have gained 16.24HP. Realisticly a good NA boat engine makes around 1.15HP per cube so in all actuallity you will gain 8.05HP. Now bore will help unshroud the intake valve so it does help flow but boring doesn't gain you as much as putting stroke to it. Take that 502 and put a .250" more stroke in it with a stock bore gives you 532 CID. Now times 30 x 1.15 = 34.5 HP but with the longer arm you gain a broader torque band. A broader torque band is what a boat engine needs, power from 900 rpm to 5500 rpm. Stroke gives you that lugging power to move the boat, the friends, and livations in the cooler :D

[kevnmcd]

Your welcome.
Just a note about cubes. I am a huge fan of cubes but boring a block out to get 10 more cubes doesn't really gain you anything. Lets look at it this way the best Cup engines make around 830HP out of 358CID. Thats 2.32~ HP per cube. So if you go from 502 to a 509 at best you have gained 16.24HP. Realisticly a good NA boat engine makes around 1.15HP per cube so in all actuallity you will gain 8.05HP. Now bore will help unshroud the intake valve so it does help flow but boring doesn't gain you as much as putting stroke to it. Take that 502 and put a .250" more stroke in it with a stock bore gives you 532 CID. Now times 30 x 1.15 = 34.5 HP but with the longer arm you gain a broader torque band. A broader torque band is what a boat engine needs, power from 900 rpm to 5500 rpm. Stroke gives you that lugging power to move the boat, the friends, and livations in the cooler :D
Makes a lot of sense when you put it in terms I can understand....SIMPLE! :D

[cstraub]

KISS Keep It Simple Stupid!!! Thats me. Let me know if I can be of any more help.
Chris

[Beer-30]

Good info.

[Krumbsnatcher]

:D You be welcome.
Heads, cam and exhaust should get you there.
Tyler Crockett had a 100-110 HP bolt on head, cam kit. I am sure he still does. Uses your heads or swaps you for another pair. Kinda like the Raylar kit for 496s, except Tyler sticks with iron heads. Alum would get you probably just a few more HP, but also a weight savings. Edelbrock has a nice bolt-on pair that I was looking at before I ended up with a 496.
Edelbrock heads: (directly from their site)
http://www.edelbrock.com/automotive_new/mc/heads/images/60459.jpg
MARINE-DUTY PERFORMER RPM 454-O AND 454-R
Heavy-duty, 1.89" Inconel exhaust valves provide added durability for marine applications
Hard anodized to protect the aluminum in the harsh marine environment
Sold with valves only to allow for valve spring choices
Match with an Edelbrock Performer RPM manifold, Performer Series 750 cfm marine carb and Performer RPM cam for proven performance
Smaller-than-stock 11/32" valve stems promote excellent flow and lighter valve weight
PERFORMER RPM 454-O MARINE OVAL PORT
Chamber Size Intake Port Size Valve Sizes (in/ex) Bare (single) Complete (single)
110cc 290cc 2.25"/1.89" N/A #61459*
PERFORMER RPM 454-R MARINE RECTANGULAR PORT
118cc 315/300cc (long/short) 2.25"/1.89" N/A #61559*
I have been running the auto heads but i switched the exhaust for the marine ones $259 get em autozone.
I have a stroked 540 that was blown that i am converting to an EFI system this winter. Just waiting for the parts to come the block is ready to go.
I have an ISKY Custom grind cam 114 deg at .612 lift for I/O
Good luck.

[Beer-30]

Crane 168731 looks like a nice cam also. :wink:

[BOBALOO]

Here is a good thread from OSO on what you want to do. You might want to lose the fuel injection to lessen the tuning headaches. I think an ECU recalibration would cost at least 300$ so you could put the 300$ towards a new carb, and future changes would be a jet change away.
http://www.offshoreonly.com/forums/showthread.php?t=106621&highlight=flat+tappet

[Beer-30]

NEVER go backwards. Carbs are soooooooo 2000.

[kevnmcd]

Here is a good thread from OSO on what you want to do. You might want to lose the fuel injection to lessen the tuning headaches. I think an ECU recalibration would cost at least 300$ so you could put the 300$ towards a new carb, and future changes would be a jet change away.
http://www.offshoreonly.com/forums/showthread.php?t=106621&highlight=flat+tappet
Thanks for the link, Bobby. I am going to stay with the EFI though. I would rather adjust the ECU once rather than adjusting the carb all the time. :shift: