[Aaron75]

What's the most measured hp folks have gotten out of a 455 w/ #64 heads?

Thanks in advance.

Aaron

[kyle_blake]

I think the stock 1970 - 455 ho had something like 360 hp and 500 lbs of torque.

Rare head for a pontiac, I saw a bare set on ebay go for over $1000

[Aaron75]

The 360 is a number I've seen folks toss out here, but I've a '70 shop manual that has the '64 heads (455HO) going at 370hp, ranked the same as the RAM Air III. Who knows what it really is, but being a '70 455HO owner, i always chime in w/ a 'its 10hp more' comment just to make myself feel better.

They being rare heads i guess not many folks would have much experiance with them. I was asking the question, because i was wondering what would be a reasonable amount of horsepower to assume to get out of a stock '70 455HO engine w/ new innards. (Basically porting the heads, new pistons, rockers, etc. but keeping the intake maniflod and the heads themselves.) I actually switched out to the RAM Air exhaust because theyd on't look that far off from stock and you can get them powder coated. Woo woo.

Aaron

[kyle_blake]

I run the #64 heads on my 400 pontiac.

I believe most pontiac advertised hp was at the engine dyno. Not sure.

I remember going holy crap on the torque at 500 lbs with the cam they use in those..

Not sure it's a special HO cam or the standard 068 or whatever.

Others would know for sure.

Yah I'd think for sure 300+ horse at rear wheels and 400 pounds of torque at for sure if not more.

V-cool on powder coating exhaust manifolds, I didn't know you could.
If you choose a clone of the 455 HO cam then you'd be really close!
Or choose one thats a little bigger but works with your stock stuff.
If possible.
Cool! Sounds fun!

[zippy]

I'm running approx 400HP at the wheels with my 455/#64 head combo. I have a HO-enterprises HC-03 cam, 243/250 dur .533 lift w1.65 rollers and Rhoads lifters. and the heads have had gasket match and bowl/runner cleanup.

$1000 bare on ebay, Hmmm. I've been thinking about a KRE Alum head upgrade. Nice to know I mihgt be able to get some $$ for mine, but I just might hang on to them for future.

And ya, you powdercaoat things that will see up to prolonged service temp. of up to 1000F, but the color choices are limited. Ceramic coat will last to about the same temp indeffinately. Sustained temps of 1200*+ will cause tarnishing, but no deterioration of acctual hear barrier. There's another coating too. It's a "satin Black" and is good to 2000*F

[berrygoat]

If I remember correctly, 15's on a 2 bolt 455 had slightly lower compression than 64's and small valves. The engine with 15's was 360, the HO with 64's was 370.

Zippy, I ran your same combo (with Bill Miller Alum rods) with 1.5 rockers in the late 80's in a 74 TA. Back then I had no idea how to tune a car for best performance. With a a Torker 1 and an 800 Holley DP that car was an absolute monster. (On Cam 2 gasoline)

[zippy]

Anyone have flow #'s for the #64? I am interested to see how much more I will get with Alum's

[rexus31]

I'm running #64's on my 400 with a '65 Tri-Power, 1.65 roller tips on intake and 1.5 roller tips on exhaust, stainless valves, mild cam: 216/216, .499/.454, 4 speed, 3:55 gears. Runs strong, 2nd gear is a monster. The best thing: I can run 89 octane if I have to with full timing, no detonation. I still run 91 just to play it safe. Compression checks out to about 8.4:1. I think they are the perfect head for a 400 street motor.

[Aaron75]

Zippy 400HP at the wheels wow. That’s not w/ a stock intake manifold is it? What sort of compression are your cylinders at?

I've a 280/286 duration cam w/ .455/.468 lift, 1.5 rockers. According to the chassis dyno i'm at 275hp @ 4300 rpm at the rear wheel (w/ a M21). A clutch fan (currently flex fan) would probably allow it out to 4800 rpm or so giving it possibly another 5 hp, but that still seems low...

I'm thinking the compression (8.5) might have something to do w/ it sitting so low, but when I calculate the change in hp between 8.5 and 9.5 its only something like 3%. So then i thought this whole dynamic vs. static compression (cam selection) thing might have something to do w/ it, but when i calculate that i'm sitting in around 7.9 or so (between the 7.5 and 8.5 that seems to be recommended).


W/ respect to the powder coat, Ram Air have a grey powder coat on the ceramic that looks pretty close to 'new' cast iron. That's the route i went.

I'm a bit of a novice, so bare w/ me if something i've said doesn't make sense.

[kyle_blake]

aaron-> I have domed pistons which brings up my compressions to 10:21:1 so my 300hp seems about right at 3% per point of compression.

You've had your car on a real chassis dyno or is this the computer dyno program?

[Aaron75]

real. I was trying to make sure the carb was running properly. Fuel always seemed a tad rich to me by smell. Turns out it was running a bit dry at crusing speeds.

Yeah that does sound about right then so that makes me happy.

Thanks for the help

Aaron

[P@blo]

1000 bucks!!!! I just traded a 70 455 with the 64 heads for another 455.

[potentpontiac]

I did a port job on a freinds GTO and had good flow #s in the 550-575 lift range.We got 258cfm intake@550 lift and [email protected] chassis dyno showed 491HP at the flywheel.The car is 3960lbs total race weight and has gone 11.50s in good air.The short block is 040 flat top pistons 0 deck,stock crank 4.210.Cam is a solid grind comp,cams around 565 lift.His short times are in the 1.60 range.Performer intake with 750HP holley carb.This car is very competitive and outruns his freinds GTO same year with ported E heads.Steel heads work with the right amount of porting and attention.

[zippy]

Originally Posted by Aaron75

Zippy 400HP at the wheels wow. That’s not w/ a stock intake manifold is it? What sort of compression are your cylinders at?

I've a 280/286 duration cam w/ .455/.468 lift, 1.5 rockers. According to the chassis dyno i'm at 275hp @ 4300 rpm at the rear wheel (w/ a M21). A clutch fan (currently flex fan) would probably allow it out to 4800 rpm or so giving it possibly another 5 hp, but that still seems low...

I'm thinking the compression (8.5) might have something to do w/ it sitting so low, but when I calculate the change in hp between 8.5 and 9.5 its only something like 3%. So then i thought this whole dynamic vs. static compression (cam selection) thing might have something to do w/ it, but when i calculate that i'm sitting in around 7.9 or so (between the 7.5 and 8.5 that seems to be recommended).


W/ respect to the powder coat, Ram Air have a grey powder coat on the ceramic that looks pretty close to 'new' cast iron. That's the route i went.

I'm a bit of a novice, so bare w/ me if something i've said doesn't make sense.

around 10:1 comp, highly massaged Edel Performer intake with 3/4" open spacer. Gasket matched intake and heads, slightly ported #64's 1 3/4 headers. with open 3" dumps. Last time at the track, it computed to just over 360HP to the wheels, but that was with way to tall gearing, stock tires and a converter that is more solid than Rosane Barr's love for the twinkie. with proper tranny/suspension tuning, 3.42's I know it'll pull low/mid 12's which should be approx 400 at the wheels.

But ya, until I get a real chassis dyno, and do some tuning, I know it's alll speculation and blowing smoke, but my combo does have some bawls but it's lacking somewhere, and I havn't run enough Pontiac's to know where I am lacking

Ohh ya, all running a stock Q-jet from a 77 350. Needs some tweeking