Let's play the "HOW MUCH HP" game!

Ok, starchief1959 and I started a conversation about beefing up our '59s. He said he wants about 400 hp. Me too, I'd like to think that's about where I'm at.

This is what I said from our previous thread

"According to some guys on performance years, they think my motor is only about 300 hp. I think they're stoned and mistaken.

Hardly anything is stock, and the headers over stock manifolds has to be good for at least 25 hp alone, not to mention way better valvetrain, way better cam, better carburetion and better ignition. So how my motor went from 315 hp stock to less hp with all the money I have into it, I don't know. They said because 315 is the old school rating, SAE would be about 10% less. So I guess that would mean I'm only making about 20 hp over stock? That sounds ridiculous to me.

Even on new vehicles, I know 2 guys that did dynos before and after headers, they both got over 30 WHEEL horsepower over stock manifolds.

The heads are completely redone, There is nothing stock or reused in the heads, the only thing stock on the motor is the crank and rods and pushrods. Honestly I don't see how mine is any less than 1HP/cubic inch. It better be at least 389 hp. But whatever, we'll find out how she runs soon enough.

Honestly, I'll be pretty disappointed if it runs over a 14.5. I think at 4300 lbs it needs about 375 hp at the crank to run mid 14s.

When I first discussed my motor build with the guy who built he he said "400 hp easy, probably more like 450" 450 sounds exageratted to me but I don't see how 400 hp isn't reasonable."

Here is a little more details about my motor, tell me what yall think


It's the original 389, fully rebuilt, bored 30 over, stock crank and rods, stock length but new pushrods, everything else is new, dual carter afbs freshly rebuilt on a Offy intake, full length headers, all MSD ignition, the heads are completely redone with nothing stock or reused, crane roller rockers, ARP screw in studs, stainless steel valves (which I think he said were from a chevy so the heads had to be machined to accept the bigger valves) and the oiling was converted to pushrod oiling, the cam is a crane hydraulic street cam. I have the full invoice on it if you'd like to see it. When i asked him how much HP he said "400 easy, probably more like 450" I think 400 hp is a reasonable guess. Stock tri powers were rated at 10.25:1 compression and 315 hp.

Chris, chime in with your full plans if you have it all planned out already.

I think the only thing I would do differently with my motor is I would take it to a Pontiac guy. I'm taking the 389 out of '62 to Pontiac Larry from Performance years. He's an engine builder and he knows Pontiacs. He gauranteed me the best price and performance. I'm looking for 450+ HP in that one. It's gunna be stroked to the max and have a good port job on the heads. I wanna run 12s in my '62.

I'd probably get the heads ported also, it's not too late for that though.

I'll just be happy to get out to the shows and make it back!!! LOL!!

Me too, but why not get there as fast as possible? haha

Not sure about all my final plans yet. I have to get it torn down and look at things. Need to get some info from my machinist on what we can do with the heads cause if the valves are too small I'll be swapping out heads, intake, and timing cover assembly.

Get me the specs on your engine and I can run a dyno program that graeme from HCP sent me. He said it's usually accurate to about 5% of actual. I'll need ALL specs right down to valve sizes and carb CFMs, etc. We'll get you a fairly accurate number to go by.

Let me know exactly what you need, I tried the program I have but it doesn't have dual quad on it and I don't know my head flow numbers. I've gotten anything from 300hp-500hp

And your valves are smaller than other years but you can get them machined for bigger valves. I'm pretty sure that's what the guy did with mine, but it's been so long I don't remember exactly what he did. I do know that I will be putting the biggest valves I can in my '62 build.

I'll need the following...
Bore, Comp ratio, cam specs, rocker ratio, int port, chamber cc, int and ex valve sizes, carb CFM ratings, exhaust primary, collector, inlet, and exit diameters. That should about get it. I know your ignition system.

I will need piston specs too if you're running domed.

I bought a book on building performance pontiac engines, and i was dissapointed to find out that the only statment regarding my heads were that they had smaller valves than later years, and were not usable for a performance engine. That is the only bottleneck i can think of...

That's why I was pondering having them ground for a larger size or just swapping to newer heads. However, with newer heads you need a new intake manifold and timing cover also.

Bore is 30 over (I'm not sure what stock is off the top of my head)
Comp ratio should be stock 10.25:1
rocker ratio is 1.5
int port????
chamber cc???
I think stock intake is 1.88? exh is 1.66?
carbs are 550 each so 1100
ex primaries are 1 5/8"
collector is 3" and will be either 3" or 2.5" all the way back

The only cam specs I can find now are
Crane Hydraulic lifters with Crane roller rockers

Intake duration 284
I think exhaust is the same because on the sheet it only lists that #

Same with the intake and exhaust lift, only lists one number .48

Lobe separation of 112

I've tried to find out the exact size for the valves and chamber cc but haven't had much luck. What's intake port looking for?

I do have a spare head I guess I could measure the CC with one of those measuring kits.

I've got a program that asks all that stuff, I'm going to run it again and let you know what i input and lets you know what i get out of it.

bore- 4.093
stroke- 3.75
intake cc 160 (closest estimate I could get, I'd like to think it's a little higher)
intake valve 1.88
exhaust vavle- 1.6
I have compression at 10.25 which is stock
Pistons are stock style flat tops
hydraulic lifters/roller rockers
284 duration
.48 lift
advance 10* (guess)
lobe separation 112*
carb induction
.5" spacer height
1100 cfm
T ram
Exhaust- racing duals???
total advance 28* (guess)

336 hp @ 5250
375 tq @ 3750

That's lower than a stock motor on torque and not much better on hp.

Switching the intake to "dual" gives me 455 ft lbs at 2500 and 308 hp at 4250. I don't know if that's dual quad or dual plane

Switching to single gives me 375 tq @ 3250 and 304 hp at 4750

Using the same program, vehicle weight of 4100 and driver weight of 150 1/4 mile estimate of 14.73 with the "dual" and 14.34 with the tunnel ram, even though the torque is a lot less.

I don't know, I'd like to see 14.00@95mph after a few runs at the track. I think it's reasonable.

I ran the numbers and got about the same as you did, about 330hp. The biggest limiting factors I could find were the rockers and heads. Just not getting enough air/fuel into the engine. That's why I was talking about bigger valves earlier. Will have to make the intake ports larger too.

I've run mine with a few changes to those items and can push it up around 440hp reasonably.

What do you mean the rockers?

Still doesn't make sense how with all those upgrades I'm only make a few more hp over stock.

You should run all stock numbers in there and see what you come up with

What was your engine originally, I'll get you the stock HP rating? Also, check your compression ratios again, 10.25 seems kind of high unless you got one of the oddball engines. The majority of '59s had a 8.6 compression ratio. I'll have to do some research cause I don't know the original cam specs, etc.

As far as rockers, if you went with a higher ratio (IE 1.65) you would pick up a decent amount of horsepower if you combined that with the intake ports and increased valve size.

My motor was originally the 315 hp tri power automatic with 10.25:1 compression.

http://www.wallaceracing.com/cgi-bin/engine3.cgi

There's a chart of all the 59 motors. Mine is the C engine code. Actually that says it's 10.5 but I think that might be a typo. From what I've learned only the 4 bolt main motors were 10.5:1. They achieved that by milling the heads a little bit to get a little more compression.

It kind of sucks that more guys don't know about '59s. It's damn near impossible to find out anything about our cars. You could ask about a 64 gto and get millions of answers but no one knows shit about '59s. Sucks for us

What did you do with the tri power setup? The info I have from NHRA technical specs lists the comp. ratio as 10.5 for that engine also. In all actuality you're not really pushing anymore air or fuel into the engine over the tri power so your carb setup isn't going to gain you too much other than coolness factor.

I still think it's your ability to pull in more air/fuel that's limiting you.

The cam is still way better, Valvetrain way better, my exhaust is way better, ignition way better etc. Look at those log manifolds and then look at the headers. Those headers have to increase the flow by 500%

The tri power set up was gone when I got it. Must have been switched out sometime. But the car had tri power emblems on it when I got it and the motor is a C code.

Another thing, I highly doubt that our motors were maxed out as far as hp goes from the factory. Everything I have done to it is either stock or better than stock. It should have more power than stock.

The limiting factor is definitely the heads but that doesn't mean there is NO power left to be gained with the rest of the motor.

But if you can't get anymore air in, you're not going to be getting anymore out. If you're not in a rush to get it going I'd port the heads and open those baby's up. With the other changes made that will drastically improve what you're getting out of the engine.

Play with the engine program graeme sent us and increase the port size. There's a HUGE difference in what you can get out of the engine.

So what are your plans? Port the crap outta the stock heads or go with newer heads?

The newer heads don't really have much bigger valves and I doubt they flow a lot better. Edelbrock heads are just too much damn money, I think. On my 62 I'm gunna get them ported and shove the biggest valves I can in there.

For my '62 I think with a 4.25" stroke it'll be 447 cubic inches. All that torque from the stroke with a good port job on the heads should give that "little" Grand Prix some balls.

Haven't gotten to the point where I'm ready to pull the engine. Going to be a few years yet before I do that so I haven't done all my research yet. I'm very picky in what I do and will get as much information as possible before making any final decisions. I'm sure I'll even change my mind a few times before making final plans and actually building it. As of right now I'm planning on keeping stock heads and running the tri power. I highly doubt the tri power will disappear and I'd like to port out the heads a decent amount to get some nice numbers our of that engine.

Sweet!

Out of curiosity, What does your car weigh? Or what does your title say it weighs?

No weight on the title in MN. I'm guess it weighs in at around 4,000 lbs though.

Yeah, my title says 4100. I was told that it's probably more like 4300. I don't really have any idea though. I'd say 4000-4300 is reasonable.

The title on my Buick says 4800 which seems reasonable since it's more bulky than my Pontiac. But the title on my '62 says 3200 which I know is way off. It's at least 3700.