Any PROVEN 500 hp Gen IV 454 Mags out there?
 

I am planning to pull my 454 and have it freshened up and would like to add some RELIABLE horse power. It would be nice to see 500 hp but not the biggest of my concerns. I'd like to run more power but it needs to be turn key reliable. Anyone who has built a motor like this please let me know what parts you used and what kind of power you got out of them. I DO NOT WANT TO SUPERCHARGE.

Re: Any PROVEN 500 hp Gen IV 454 Mags out there?
 

This thread may give you some ideas.

http://www.offshoreonly.com/forums/s...5&page=1&pp=20

Re: Any PROVEN 500 hp Gen IV 454 Mags out there?
 

A few ideas..... I am really looking for specific parts. Carb ? Intake? Cam ? Are the stock heads worth using? Just a few questions I have....... I want to get as much info as I can before I dig into this project. I really only want to build this engine once.

Re: Any PROVEN 500 hp Gen IV 454 Mags out there?
 

Change the block to a 502(genIV) and add je pistons ( you are going to buy them anyway) Hyd roller from crane 226/234deg, good exhaust, Holley carb 800 pri 79 sec 89jets depending on exhaust and PV, roller rockers inconel exh valves. easy 500. If you want to keep the blocks than stroke em to 496, again easy 500.
If you really want to do it once go for the added displacement and good exhaust, it is worth it.

Re: Any PROVEN 500 hp Gen IV 454 Mags out there?
 

I kept the 990 heads, stock GM aluminum intake and Q-jet and made 509hp. Is it the route most people would like to take? Probably not. I'm an old super stock drag racer so I have a lot of time invested in Q-jets and know many of the tricks (and don't mind piddling with them). They now have velcro instead of screws for easy adjustments on the fly. :D Following is a "short" list of the mods.

1) .030 JE pistons. raised compression to 9.5 from 8.75
2) EMI Thunder exhaust
3) Custom ground hyd cam 236 @ .050 and .561 lift
4) Balanced entire rotating assys
5) Crane Hi-6 marine ignition
6) 990 heads with Ferrea valves (upped the intakes to 2.30)
7)Crane gold roller rockers

The motors were turning 5500 with 23 Mirages on a 311 Formula. Right at 72mph. I was happy with them but if I were to do it over I would probably go with more displacement. The 496 ci rotating assys are a good way to go if you don't want to buy new 502 blocks. Remember, there's no replacement for displacement.

Re: Any PROVEN 500 hp Gen IV 454 Mags out there?
 

I already have roller rockers and Stainless Marine exhaust. The last owner bought those. I was thinking of some light head work for better flow and to raise compression, a better cam, carb and maybe a different intake. ALL of this after the bottom end is freshened up. I don't really want to spend the $$$ for a stroker setup or to get a bigger (502) block. What kind of $$$ is it to bore the stock block a bit and get a set of good pistons??

Re: Any PROVEN 500 hp Gen IV 454 Mags out there?
 

If your going to bore the engine you are going to buy pistons anyway. For another $600, $250 for crank and $350 for rods you can have a nodular cast stroker crank and a set of 6.385" I-beams. For 500 HP a nodular crank will run for hours. Now you have 496 inches and 500HP will be a breeze. You can run a smaller cam and have no issues with docking or idling.

Chris

Re: Any PROVEN 500 hp Gen IV 454 Mags out there?
 

Try this thread http://www.offshoreonly.com/forums/s...1&page=1&pp=20

I see now that you want to keep block and crank, still, there is some good stuff in that thread.

You may want to avoid taking your compression up much. You should be able to make that power and still run 87 or 89 octane max with good heads or good head work.

Re: Any PROVEN 500 hp Gen IV 454 Mags out there?
 

I have some left over stuff out of my 500hp motors if interested .Gen 6

Re: Any PROVEN 500 hp Gen IV 454 Mags out there?
 

What kind of power do you guys think I would have with the head work to bump the comp. ratio to 9:1, a bigger cam (maybe a 731) and a Holley 800 or 850 DP?
Is that too big of a cam?
I an running the stock ignition so I don't know how high I can rev the motor. Does the thunderbolt ignition have a limiter? I really don't want to rev it too high anyway. (5200ish)

Re: Any PROVEN 500 hp Gen IV 454 Mags out there?
 

????????

Re: Any PROVEN 500 hp Gen IV 454 Mags out there?
 

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?

Re: Any PROVEN 500 hp Gen IV 454 Mags out there?
 

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

Re: Any PROVEN 500 hp Gen IV 454 Mags out there?
 

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.

Re: Any PROVEN 500 hp Gen IV 454 Mags out there?
 

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.....

Re: Any PROVEN 500 hp Gen IV 454 Mags out there?
 

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

Re: Any PROVEN 500 hp Gen IV 454 Mags out there?
 

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...:)

Re: Any PROVEN 500 hp Gen IV 454 Mags out there?
 

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

Re: Any PROVEN 500 hp Gen IV 454 Mags out there?
 

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.

Re: Any PROVEN 500 hp Gen IV 454 Mags out there?
 

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

Re: Any PROVEN 500 hp Gen IV 454 Mags out there?
 

The crane 731 cam will work fine and idle just fine. I put one in my 454ci/525SC. As far as making 500hp with it and the rest of your combo, I doubt you will, but it won't be that far off. I would guess you will more than likely be in the 450-475hp range. I would prop it to spin 5200-5400rpms.

Re: Any PROVEN 500 hp Gen IV 454 Mags out there?
 

Will I have reversion problems with the exhaust and a 731 cam?
Will it work with my heads?

Re: Any PROVEN 500 hp Gen IV 454 Mags out there?
 

I don't know anything about the lift limitations of the 990 heads--They are the large oval ports, right??? I've only had rect ports. Reversion should not be an issue with the SM exhaust.

Re: Any PROVEN 500 hp Gen IV 454 Mags out there?
 

Don't mean to interrupt, but I believe 990 's are the same as 188's.

Re: Any PROVEN 500 hp Gen IV 454 Mags out there?
 

I paid $1,200.00 for a used 502 block. I was told $1,800.00 new from GM.

Re: Any PROVEN 500 hp Gen IV 454 Mags out there?
 

After putting new bearings and re-ringing the 454 I definately do not want to buy a 502 block..........
I am done except for cam selection..................... Any more ideas guys?
I have 731 and 241 as suggestions. What are the pros and cons of the 2 cams?

Re: Any PROVEN 500 hp Gen IV 454 Mags out there?
 

I've used both cams. The 731 is a roller cam. The 241 is a flat tappet. The 731 will probably make about 20-30 hp more than the 241. The 731 will cost about $800 more for the cam and lifters and valve springs you will need.

The 241 cam is available in a kit with lifters for about $150. I have the exact part #'s at home. I'm at work now. The 241 cam is very close in specs to the stock 420/525SC cam.

Re: Any PROVEN 500 hp Gen IV 454 Mags out there?
 

Is there a tappet cam that would make more power then a 241?
If I can make good reliable power for less $$$$, I AM ALL FOR IT!!

Re: Any PROVEN 500 hp Gen IV 454 Mags out there?
 

I will have dyno sheets Monday night, will post when I get them...

Re: Any PROVEN 500 hp Gen IV 454 Mags out there?
 

Yes, there are bigger cams that will make more power, but you will have to spin the engine at higher rpms. You will also loose some midrange power. That cam is good to 5400 rpms.
The crane part # is 134241. The part # for the cam/lifter kit is 134242.

specs are 226/236, .534/.553 on a 112 lobe sep.

Re: Any PROVEN 500 hp Gen IV 454 Mags out there?
 

Any ball park figures on hp with the 241 cam, Holley 800, roller rockers, 9:1 comp and stainless marine manifolds?
What should I rev this thing to?

Re: Any PROVEN 500 hp Gen IV 454 Mags out there?
 

Please include the details on the engine(s)...........

Re: Any PROVEN 500 hp Gen IV 454 Mags out there?
 

425-450HP.

I had the same cam in a 454mag with roller rockers. Shaved the stock rect port heads and bumped the CR to about 8.9. Ran the stock magnum intake and a rejetted HP500 Holley 800cfm carb and Imco exhaust. I gained about 4-5mph. This would translate into about a 60-75hp gain over the stock 365hp. I spun it up to 5450rpms.
The bottom end had 400hrs when I redid the top. I put 50 hrs on it and the next owner put probably 100 on it. It was still running fine as far as I know and was pulled to put in bigger power.

Here's some old threads where I gave someone similar info. He dynoed the engine and was making 420hp @ 5000 rpms. That cam will make HP beyond 5000rpms. Spin it to 5400 and should be about 450hp.

http://www.offshoreonly.com/forums/s...ad.php?t=25932

http://www.offshoreonly.com/forums/s...ad.php?t=21543

Re: Any PROVEN 500 hp Gen IV 454 Mags out there?
 

Griff,
Thanks for all the replies, you have no idea how much time I have spent looking at cam specs scratching my head..........
Also nice to hear I am not the first one to go with the cam/rollerrockers/carb/head shave combo!!
If I can I will have my motor dynoed and let you know how it turns out.
Thanks Again

Re: Any PROVEN 500 hp Gen IV 454 Mags out there?
 

Griff,
I was reading some old threads and see that you had the 454 in a 24' Baja....... I am in the same boat.
I was thinking of a rev 4 but I saw a post where you stated it didn't work well for you. What prop did you find to perform the best?
What kind of speeds did you get out of your 24?

Re: Any PROVEN 500 hp Gen IV 454 Mags out there?
 

Fastest prop was a labbed 23 Mirage plus @5500 rpms. Saw about 65mph with it. Best all around ride was a 24 Bravo @ 5100rpms @ 61mph. Much better cruise speed and holeshot with the Bravo 1 and eliminated the porpoising that 24 OL's get easily.

Re: Any PROVEN 500 hp Gen IV 454 Mags out there?
 

Get with Bob Madera, RMBuilder on this website. Give him all the information and let him select a cam for you. He is the best at this. Your combo should be good for about 450 HP.

Re: Any PROVEN 500 hp Gen IV 454 Mags out there?
 

Alright I will contact him.....

Thanks