WA 2 FST

Engine in question is a 454 4-bolt, forged crank, Keith Black hypereutectic pistons, ~9.5:1 CR, Comp Cams hyd. roller (11-422-8) w/ GM Performance Aluminum Oval port heads and GM hi-rise manifold.

It's mild.

Would like to build a combo that will make plenty of TQ and streetable HP... spin it to ~6200rpm (so peak HP would be ~5800-5900rpm) and continue to use a hyd. roller cam (obviously larger than the current one). Looking for ~460-480rwhp out of it. Don't mind some lope, but would like it to idle under 1000rpm... oh, and did I say I want to make gobs of low-end TQ. Rear gears are 3.36, tranny is a Tremec TKO-600.

AFRs? Brodix (oval or rectangle port)? Others?

Hood is an L88 copy, so I'm planning on running a high-rise... something like an Edelbrock Air-Gap.

Thx.

StraubTech

You can go 2 routes. Have your heads tuned and new parts to achieve your goal or go with a set of aftermarket heads in the 265 to 270 cc range.

With the Morel hyd roller lifters they will spin to 7500 rpm. I have an iron headed 427 in a Impala around NYC that shifts at 7500 rpm with a set of Morels. At 4700# that car runs 10.90s'.

Super6

What heads do you have? The GMPP 110cc combustion chamber ones or the 100cc set? Either way your compression is on the lower side to be thinking about a cylinder head with much more combustion chamber volume. That limits your choices right there. I may be wrong, but I'm a proponent of keeping the compression as high as you can. Particularly if you are looking at 600 flywheel HP, like you are. I have both of these cylinder Edelbrock made heads and you can have them worked over and get around 335 cfm out of them at 650 lift.

If you have header/side pipes, that eliminates using heads with raised exhaust ports, due to interferences between the side pipes and the body.

Brodix Race-Rites Oval ports might fit the bill, but I can't tell from a quick look at their website what the chamber volume is. It is more than 110cc from memory.

WA 2 FST

Super 6, they are the 110cc chamber GM HP Ovals.

I agree 100%... would have to have them milled... easily done with the AFRs, I know for sure. Definitely do not want to decrease effective CR.

garygnu

what do your current heads flow ?what could they flow with porting ?stick with oval port heads ,they work good on engines up to 500 ci.check the comp cams catalog,or call them for a torquey cam.

zwede

Your current heads flow 300 cfm @ 0.600 lift. They're not bad heads. You can step up to Brodix race-rites or AFR and they'll flow 10%-15% more out of the box. Or you could have your current heads ported and save some money.

bluedawg

Sorry to high jack but what do stock 791's flow?

bmans vette

I agree with the heads recommendations but higher CR will be needed for your goals.
The weak link becomes the hyper pistons.
What brand/type rods are you running also?
I would think all-forged lower end would be necessary.
Good luck with your build.

IMO
Bman

StraubTech

http://users.erols.com/srweiss/tablehdc.htm

the more a head flows the less cam it needs...... What?

If we do something quicker, then that means it takes less time.

Duration is time. If a head flows air at low lift numbers then it is filling the cylinder quicker. Quicker means it will take a shorter amount of time. Duration is time......use less duration.

WA 2 FST

Markus, thanks for the reply. Good to see you still have your hotrod.

I'm the guy who had a '69 vert about 10yrs ago... did a "top-half" build and it ran great... should never have sold the car, but stuff happens and you do what you have to do.

A little background for everyone else... I had a '69 454 roller valvetrain motor with 9.5:1 CR and went from iron head ovals to AFRs and a small cam (230^ duration on both intake/exhaust) was very pleased with the results. (~440rwhp)

Was just checking to see what the consensus was nowdays ... given it has been a decade.

bluedawg

I get ya there Chris that the better the head the less camshaft you need to maximise the combo. As you know I just bout a 454 and it has 781's on it. Deep in the planning stages and am thinking 496. I read mark Jones built a 496 that 800 horse using 049's. Pretty sure I'll end up using afr's because I've never ported a set of heads and Mr. Jones is a master at this. Just curious to what they flow, the link I think showed that they flow around 270 at .500". Thanks for the link.

badrad

I think bang for buck would be some porting, since those tend to respond well to it, and a hyd roller cam from Chris Straub. I have a set of lightly ported RPM-M heads and they picked up 60cfm at .650" lift. Chris touched on it but the right cam will do wonders for your mill.

zwede

I remember you & the car. It was a nice ride. Shouldn't have sold it.

WA 2 FST

I hear ya. I have found another one that is in impeccable condition...recent frame-off resto with new suspension/brakes and the guy had the above engine built (~2000 miles on it). It has an EZ EFI installed + the Tremec TKO... probably a pretty nice ride.

I just figure I won't be able to leave it alone and will want more power.

tt 383

Send them to Dr. J's for the 305 Airwolf port job, nice flow numbers on their site and they would allow room to grow. Waste of money going to a Brodix Race Rite on a semi moderate build IMO. I really think a good cam and keeping the compression up will get what you want. You could have them milled, valve job, and a minor port job (bowl blend and guide profile) by a local performance shop you trust. You do have a few options to play out just depends on what you want and how much you want to spend. I wouldn't worry about low end, and if you run a real sized tire you will likely want deeper gears to get the OD in the proper rpm considering the cam will be somewhat healthy in duration. One last thought, not sure how good that particular intake is, but it probably doesn't flow what your heads do stock and is likely the choke on induction side at least at the top of the revs, and on the flip side exhaust will need to be up to par for that kind of power

StraubTech

A cam change in a ZZ502 combination with lifters and springs can wake the engine up 100HP. The right cam can do wonders. My customers will tell you this.

427Hotrod

Marcus...is Trevor still around Dallas area porting heads? He did Nick's. He used to be an instructor at SAM down in Houston and did my old Merlin heads. He does really nice work for reasonable prices...at least he did a few years ago.

JIM

zwede

Jim, don't know if Trevor is still around. You got your car running yet?