What does it take for 500+hp (adding 100+hp)

[Legal Chemistry]

So right now I have a 454 w/~375-400. It spins an "A" to ~4900 -whatever that comes out to be on the calculators. With the not-so-off season around I've been trying to get suggestions for what it would take to get a reliable ~500hp. I'd like to stick w/my existing heads -they are only a year old, use pump gas (91 here in SoCal), and no NOS (although it would be fun.) The boat is a cruiser, so I'm not looking for huge speeds -just a solid pick up in power with reliability.
It's a '96 454, 990 rect port heads, 9:1 compression. The carb is a Q-Jet -that will be changed out. The recommendations so far have been change cam & carb for a solid & safe 500-500hp (0.636 lift 256 duration @ 0.50 on a 108), with a 1050 carb. Any other suggestions? Ideas or recommendations? What will the parts list consist of and $?
If this combo is good for a reliable 500+hp... I'll be one happy camper!
Thanks!
LC

[MudPumper]

500 hp from a BBC is a piece of cake on pump gas. There is no way you will need or be able to use a 1050 carb. 850 at the most.

[n8dawg]

You would make well over 500 hp if you bought some new heads. I understand you wanting to keep them, they cost a pretty penny. I dont know anything about that casting of head but a port & polish job would probably let them breathe a whole lot better. A new cam and carb will make a difference but what intake are you running and are you running headers?

[cstraub]

Holley 850
Airgap high rise Dual Plane
Bowl Blend on the 990's and gasket match intake and heads
Matched cam to CID/rpm/Head flow in a hyd roller profile.

[469 the coyote]

The motor that we have in my moms hydro makes 550-600HP. It has merlins that are out of the box, with 10.1 comp and a 630 lift roller. The carb is an 830. You will never need a 1050 for 550hp way to big of a carb. I have tried a duel plane and an open plane and did not see any differance. For a lake boat I would go with the duel plane. Just my 2 cents.

[sbcokeman]

you didn't say how much you would spend?. how about a procharger?. 3LBS boost would do it plus be easy on the motor. 1050 way to big.

[SmokinLowriderSS]

IMO the rectangle port heads are a bad match for a 5,000 to 5,500 RPM 454. A set of '049 large oval ports (the older '781's are scarce, and virtually identical) with a stage 1 porting job and the large stock valves (2.19/1.88) would be a much better fit. Porting as noted by cstraub may help.
Are you running headers? If you have log manifolds, IMO, you are screwed much over 400HP.
cstraub would be a good cam source. He's a fine grinder that knows his stuff.
Also, his advice for intake is my intake, and would be great.
My 454 is only running arround 8.3:1, with stock '049 heads (2.06/1.76 valves), Performer RPM Air Gap 2.0 manifold for oval ports, .565" x 232* (@.050") custom hydraulic, and Lightning headers thru-transom.
5,000RPM solid, Berkley "A", 400 HP, under a 700 CFM Holley.
The heads are right now at a local racing shop with lots of boat engine (including jets) experience, Stage 1, increase valve sizes, port match intake, reduced valve stem size. $1500
They say they can and will outdo the Aluminum Edelbrocks. :idea:

[Legal Chemistry]

Thanks for the replies.... I know this board has tons of bbc gurus! Here's a little more info to chew on :D
The heads are:
12562920 Cast Iron Gen V & VI Cylinder Head Assembly Gen V and VI cast iron head with 118cc open chambers, rectangular intake ports, and 3/8-inch rocker stud holes. 2.18-inch intake valves, 1.88- inch exhaust valves.
No logs, just the stock merc manifolds. It's a closed engine bay -so it would have to be water jacketed $$$$$! The intake is an takeoff (so I was told) of the RPM Performer.
A blower sounds good, but the belt would require moving the rear bench forward... not really the best option. For now I'd like to go with a engine combination to achieve this -on paper it seems resonable.
Cstraub, what do you think would be fit for this combination? An 850dp & cam? What else is needed to make this happen.
...still learning!

[SmokinLowriderSS]

I don't think the manifolds will help you, but I don't think they are as bad as the old log manifolds are.
Jacketed Lightnings like mine will set you back aprox. $1900, plus 4" tips if you don't have already. (another $200)
Trying to find some info on the heads. So far, all is just specs on the heads as you posted.
No way arround needing adjustable valve train parts to replace the stock Gen 5/6 fixed stuff, unless they are already set up adjustable as you have them.
I claim no guru status, I'm just trying very hard to maximize my 454, with minimum outlay of cash (sometimes a hard comodity to find). That includes reliability as well. It has given me a good feel for what works well. I have little doubt I will see 500HP or better come spring (that 700 CFM carb has to go away tho finally). Should get just under 6-grand on the nitrous and that is too much for the 700 to keep up with.

[gr16241]

Holley 850
Airgap high rise Dual Plane
Bowl Blend on the 990's and gasket match intake and heads
Matched cam to CID/rpm/Head flow in a hyd roller profile.
Perfect advice!! Just add headers and a good ignition.

[pw_Tony]

Lightning headers= $$$$$

[396_WAYS_TO_SPIT]

The recommendations so far have been change cam & carb for a solid & safe 500-500hp (0.636 lift 256 duration @ 0.50 on a 108), with a 1050 carb. Any other suggestions? Ideas or recommendations? What will the parts list consist of and $?
I ran a cam with similar specs and it was a nasty setup. The problem is that the lobe is too tight. It will suck water back in your exhaust. You would have to run dry headers on a 108. Not to mention that it will make hp in the higher rpms.

[Legal Chemistry]

I ran a cam with similar specs and it was a nasty setup. The problem is that the lobe is too tight. It will suck water back in your exhaust. You would have to run dry headers on a 108. Not to mention that it will make hp in the higher rpms.
Thanks 396, that's the feedback I'm looking for. I definitely want to avoid reversion!!!! I don't want to make these changes to find out I'm up sh!t creek later. The best advice is usually from a tried and tested combo.
Back to the carb/cam combo with cleaning the heads up a bit. I'm guessing this will be in the <2k range? I'll still need to source up the best cam profile for my application.

[TJS]

I just finished putting together a Gen IV LS-6 block 454 .030 and used the comp cams roller for jet boats. Don't laugh, this thing runs strong. Hyd Roller.
.566/.566 Adv .296/.302 242/248@50 Lobe Sep 112. CCA-11-456-8. I am also using Brodix BB-2's CNC ported and SRP pistons with eagle rods and factory forged crank along with a E-brok RPM air gap and proform 850 carb. I am running a B Cut dominator impeller in a Berk JG. It hits 6000 RPMs in no time and stays there with no problems. I am using Duane's Ultimate wear ring. I emailed him and he states I am over 600HP. IMHO it all comes out to to proper block prep machine work and esp. the heads.
T.J.
www.tjsperformance.com

[pw_Tony]

I hope these guys know that Legal Chemistry's boat is a BIG jet boat. Not sure how well a big duration camshaft can help with a heavy boat, but I'm not sure, I'm just relating to cars

[Sleeper CP]

Holley 850
Airgap high rise Dual Plane
Bowl Blend on the 990's and gasket match intake and heads
Matched cam to CID/rpm/Head flow in a hyd roller profile.
:D Yeah, what he said.;)
Back to the carb/cam combo with cleaning the heads up a bit. I'm guessing this will be in the <2k range? I'll still need to source up the best cam profile for my application.
You not going to find any better source than cstraub69, send him a PM would ya, and be done with it, unless you just want to up your post count;) :smile_sp
For you head work there are a lot of people here in San Diego Count that can do it. I would suggest my friend Geoff Mummert who did a lot of work on my big Ford including all the trick head work. You can reach him at 619-596-0312
He does great work at a very good price.
As far as the cam goes, I would go with a custom grind and a hydr. roller is hard to beat. You could probabaly check with Crower,Comp, Crane or Isky and get a okay catalog cam but a custom cam is realy the way to go.
Lastly, I personally would like to see you raise the compression to 10:1 if possiable. Just my .02
Good luck.
p.s. I run custom Crower stuff in my boat, but I have Dan Crower @ www.crowerpower.com do my cams. He know's his shit.
Sleeper CP

[pw_Tony]

:D Yeah, what he said.;)
You not going to find any better source than cstraub69, send him a PM would ya, and be done with it, unless you just want to up your post count;) :smile_sp
For you head work there are a lot of people here in San Diego Count that can do it. I would suggest my friend Geoff Mummert who did a lot of work on my big Ford including all the trick head work. You can reach him at 619-596-0312
He does great work at a very good price.
As far as the cam goes, I would go with a custom grind and a hydr. roller is hard to beat. You could probabaly check with Crower,Comp, Crane or Isky and get a okay catalog cam but a custom cam is realy the way to go.
Lastly, I personally would like to see you raise the compression to 10:1 if possiable. Just my .02
Good luck.
p.s. I run custom Crower stuff in my boat, but I have Dan Crower @ www.crowerpower.com do my cams. He know's his shit.
Sleeper CP
Times two on the cam and the head work :)

[Legal Chemistry]

I hope these guys know that Legal Chemistry's boat is a BIG jet boat. Not sure how well a big duration camshaft can help with a heavy boat, but I'm not sure, I'm just relating to cars
I think BIG is an understatement, :D . The boat is nearly 25'! I think it would be cool to see a jet this size running 60+. The best I've seen so far was last weekend in Havasu, 54mph on GPS (53 going the other direction.) This was with only me in the boat, full tank of gas (40-45 gallons), and all the weekend gear. I'd imagine it's good for a couple more mph with all the stuff taken out and 30 or so gallons less in fuel. Then again, I run the boat full so it doesn't really matter.
Without the low RPM resistance cars have, would a longer duration matter in a jet? I still haven't figured out this cam thing???
With that said, what speeds you think I can realistically see with another 100hp or the 500hp mark?

[Legal Chemistry]

Thanks for the info Sleeper, I'll be in touch with him.

[SmokinLowriderSS]

Yes, long duration does have an impact and IMO, a 25' boat needs a BIG impeller, an A or AA, and a long duration cam will get it's arse handed to it by a big impeller.
That is why I advised staying under 280* advertized duration, so there is still a very solid torque level, and max HP is still reached way up at arround 5500 RPM.
Not bad if you have an "A" and 500HP.

[Sleeper CP]

.
It's a '96 454, 990 rect port heads, 9:1 compression. The carb is a Q-Jet -that will be changed out. The recommendations so far have been change cam & carb for a solid & safe 500-500hp (0.636 lift 256 duration @ 0.50 on a 108), with a 1050 carb. Any other suggestions? Ideas or recommendations? What will the parts list consist of and $?
Thanks!
LC
FYI as a comparison our 512" Ford was 10.25 comp. good alumi A-460 heads, single 1050 carb it made 710 hp at 6,000 and 682 at 6,250. I told Danny Crower that I wanted it to be done at 6,000 and it was.
It had a soild roller and the spec's were: Dur. @.050 258 & 268 Adv. was 292-301 lift was .638 on a 108 lope sep. once again this was with a 1050 Dominator. It was a nitrous engine it turned 5,200 off the bottle and 6,000 on the bottle.
So the point being don't over cam or over carb your engine. You need to stick with a 850 if you do nothing else.
Sleeper CP
Big Inch Ford Lover

[ck7684]

990's are good heads, just get a good solid roller cam and there you go...
Here's a good article...
http://www.popularhotrodding.com/tech/0707phr_big_block_chevy/index.html
This is a pretty decent book too...
http://www.tower.com/details/details.cfm?wapi=101808286

[Legal Chemistry]

990's are good heads, just get a good solid roller cam and there you go...
Here's a good article...
http://www.popularhotrodding.com/tech/0707phr_big_block_chevy/index.html
http://www.tower.com/details/details.cfm?wapi=101808286
Thanks for the links... now if I can just get it to work together.

[roscoe p coltraine]

The motor that we have in my moms hydro makes 550-600HP. It has merlins that are out of the box, with 10.1 comp and a 630 lift roller. The carb is an 830. You will never need a 1050 for 550hp way to big of a carb. I have tried a duel plane and an open plane and did not see any differance. For a lake boat I would go with the duel plane. Just my 2 cents.
And she drives it better than you do too.:D

[ck7684]

My engine is very close to that PHR build with a few differences. I am running Edelbrock heads and a slightly different cam. I am also running logs n snails for exhaust. So far I have had it to 5300 RPM but I've just barely had it in the water, and the "lake" I tested on is only 1/2 mile long, so that doesnt give me much room. I can say that this engine is hella responsive though and makes good power and should be a reliable package...:D
http://www.youtube.com/watch?v=ydiSTrHiCAg