wtpowered

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wtpowered

I'm still looking for some info on this building this motor. I am going to keep the stock heads, block, crank, and maybe the intake. I'd like to get a carb + cam, then have the heads worked a bit. What should I have done to the heads? Keep in mind I want to clean them up a bit not spend thousands making them race ready.
Would an hp 500 cam work for me? Does anyone know the #s on a stock hp 500 cam?

bobbarker

Be careful going to much lift with the cam thats where reversion comes from.

TC

wtpowered, I believe you will be limited to the amount of cam lift because of your 990 heads. Im pretty sure you will need to have some machine work done if you go much more lift than stock. I added an 850 and a edelbrock air gap intake to my stock 454 mag years ago and achieved a noticeable difference. I already had Lightning tubular headers and a MSD-6AL ignition system before the carb and intake swap. Not sure what helped the most or if it was a combination of all the parts but the engine really ran great. The engine was in a Baja 24 Outlaw and it would GPS at almost 68mph.

cstraub is right about stroking your 454!! Just this past winter I built a 496. The engine is a powerhouse compared to the 454 I spoke of earlier. It is a bit more money but the results are worth every penny. Good luck and be sure to read and study the threads on 454 buildups. There is a great deal of knowledge that one can attain on this forum.

wtpowered

68!
I have a Baja 240 (Same hull)
I have exhaust already....... Did you get the ignition so you could rev it higher?

What is it about the heads that will limit lift? I was planning on some headwork.....

Payton

There is no rev limiter on your 454 mag now. GenIV, right? I was told the stock Thunderbolt ignition would be just fine.
The 731 is a hydrolic roller cam, you'll have to get a set of the retrofit lifters to fit your block. Also your heads will have to be cut to accept the bigger springs you'll need for those lifters/cam.
Jim V is a good source here on the board for info on what to do to your stock heads to make them flow better. He talked about placing a wedge on the flow of the intake runner, porting the chambers and opening up the exhaust port. For just a little bit more you can have a set of Edelbrock alum heads.
I ended up going with a Crane 241 cam, hydrolic flat tappet. Keeping stock springs Crane Gold roller rockers, better push rods, Weiand Axcelerator intake and a Holley 800 carb. I should be around 430hp. The head work should pick you up another 40-50hp.

Jim's web site http://hometown.aol.com/valakoracehe...raceheads.html

S-24

CHEVY BB 454 EFI, 525hp/5700rpm.

MPI parts
-KMS ecm
-Holley 1000cfm throttle body
-Holley MPI intake
-MSD 38lbs injectors
-MSD 6AL

Engine parts
-Eagle rotating kit
-Merlin 269cc oval port heads
-Crane -731
-CR 9:1

RPM NM HP

3000 591 252
3500 665 333
4000 684 390
4500 690 443
5000 695 496
5500 666 522
5700 646 525

This engine was ran with the same intake with BG850dp & stock 24` T-bolt ignition, results 508hp/5700rpm.

With -990 heads you should get at least 500hp+, easily...

wtpowered

I am now looking for a good cam. The bottom end was in great shape so I just replaced all bearings and rings. I m having the stock heads cleaned, some light bowl porting and new springs, seals and retainers installed. I may have them shaved a bit to get comp ratio up to 9:1. What do you guys think of that? Good idea? Bad idea?
NOW I need to find a cam. I am going to run the stock intake, add a Holley 800 and a cam. I have been doing a bit of searching and really can't find exactly what I am looking for. I am doing the above work.... Plus the engine already had Crane Gold Roller Rockers and Stainless Marine SHORT manifolds. Any ideas???????? By the way it is a gen 4 454 mag. Thanks

Hang Time 27

Do a "search" of the Tech Q&A section of the forum with words like "500hp" and "cam", crane, comp cams, 454, etc. You'l find more opinions and info than you can read in one sitting. I'm no expert, but have always noticed that "reversion" always seems to become a factor on N/A 454's at 1hp/ci and above. Lobe seperation on the cam is very important. You might want to lengthen those stock short Stainless Marine elbows out to the tips, or all the way out the transom to make them "dry" pipes - reversion is a pain in the ass. Anyone who can weld stainless steel well would be able to lengthen them for you- much cheaper than ordering a custom set.

birdog

I have a set of GM 188 heads DONE...Stainless/Inconel valves...Porting done by Competition Marine. FRESH ..$800 takes them