[Tom Vaught]

Charlie66 with your "4 Cylinder Boosted" Pontiac Engine:

Pictures below.

85 cubic inch displacement
One Turbocharger
1026 hp at 11,250 rpm and 48 psi of boost pressure
(simple math says that 85 cubic inch engine is making well over 10 hp per cid, more like 12 hp/cid)
It uses one of Harry's Turbos, (just like you) and also inter-cooled.

Tom V.

[charlie66]

Wow thats impressive!
Thats the same turbo ive got .
I wish i had 4 valves per cyl. Thats where the power is no doubt.

That same turbo on a 2JZ made 1050 rwhp.. 4 valves per cyl as well !

[Tom Vaught]

I was pretty sure based on our many conversations that harry's Turbo was the same for the posted engine and your engine based on the numbers you gave me.

So you know the Turbo can make over 1000 HP if it has the right combination of parts on the engine and your engine is over twice as big as that one.

Tom V.

[charlie66]

Yes, Precision told me that the 6870 can make 1100hp .

It is twice as big but dont have as much valve area..

[Tom Vaught]

You nailed it. Valve Area
Tom V.

[ponjohn]

How much torque does an engine this small make?

[charlie66]

I would say 480 ft-lbs

[Tom Vaught]

Charlie is right on the number.

1025 hp 11250 rpm = 478.5 torque at 11250 rpm

https://spicerparts.com/calculators/...que-calculator

Tom V.

Before the engine went flat line on the HP (say 950 HP) at 6500 rpm the engine was making 767 torque.

[charlie66]

At 35psi and 6500 rpm my 4 cyl made 741hp and 598 ft-lbs with the old turbo. I suspect it will make quite abit more with the 6870 on it now.

[charlie66]

If things go right for me this summer with my new lower end im thinking of seeing what it will make at 45 psi . Im thinking it might be possible to get close to 800 rwhp. Precision said it would be possible to make 900 rwhp with this turbo on my engine but im not confident that thats even possible.

Ive been thinking about the design of the block alot latey because i am having thoughts about pushing the power level. It would only be just to see what it will make. Not to race it maxed all out.. Now i know there are guys out there with stock blocks making over 1000hp with out tearing out the main webs. As far as i know from reading about it they mostly split up the middle from the left and right banks tugging against each other. Now with the 4 cylinder only firing to one side with out another side fighting against it im thinking there might be a better chance of it handling more power then the V8. Im sure most of the people out there will disagree with me on this but im feeling that the cylinders will fail before it will split up the middle.. These 1961 4 cylinders are actually beefier then a 70 400ci block.. So maybe i will or maybe i wont. We will see how things go..

[Don Keefe]

Charlie, I always wondered what your combination would do with a Ram Air V cylinder head. It would also separate the center two exhaust ports, which would be great for heat management.

[Tom Vaught]

Maybe Don, after Charlie finds a 4 cylinder Pontiac Super Duty Block, he can investigate that combination. Anyone know of the whereabouts of a 4 cylinder SD block for the Traditional Pontiac is? Not talking the newer 4 cylinder version installed in some Fieros.

Tom V.

[Don Keefe]

Other than the four-bolt mains, are there any real differences in the bare block of a Super Duty four cylinder and the production 1961-62 blocks? I know the production '63 blocks were a bit thinner.

Perhaps an IA 2 block would be a good alternative, using just one bank.

[Tom Vaught]

Charlie has investigated the 4 Cylinder Blocks and says, they have a higher nickle content, better 4 bolt main caps, and other features.

Tom V.

[charlie66]

Originally Posted by Don Keefe

Charlie, I always wondered what your combination would do with a Ram Air V cylinder head. It would also separate the center two exhaust ports, which would be great for heat management.

Hi Don, I would love to try a Ram Air V head combo . It would involve alot of fabrication .

I dont know if i told you at Norwalk last year that i just upgraded my lower end and got a new head with the LS chambers and the moved spark plug location . So far im thinking from the testing ive done , i think its making more power .. Cant prove it yet, but by the end of the summer im hoping the get it back on the dyno to find out.. But theres one thing i know for sure now. Having less CFM didnt hurt the power one bit. This is an out of the box head verse the 325cfm CNC'ed one. I was very surprised ..

[charlie66]

Originally Posted by Tom Vaught

Maybe Don, after Charlie finds a 4 cylinder Pontiac Super Duty Block, he can investigate that combination. Anyone know of the whereabouts of a 4 cylinder SD block for the Traditional Pontiac is? Not talking the newer 4 cylinder version installed in some Fieros.

Tom V.

Yes! Thanks Tom .
If anyone knows of one please let me know. I let one slip through my figers once . Im still kicking myself for that ..

[charlie66]

Originally Posted by Don Keefe

Other than the four-bolt mains, are there any real differences in the bare block of a Super Duty four cylinder and the production 1961-62 blocks? I know the production '63 blocks were a bit thinner.

Perhaps an IA 2 block would be a good alternative, using just one bank.

The nickel is higher and have 4 bolt main .

As far as my understanding goes the thicker blocks started in 1961 and went half way into 1962 . Mid year of 62 they went with the thinner ones.

[charlie66]

Im not too caught up in believing that CFM is a huge factor anymore in the boost world .

I really thought with this new head flowing less, that it was going to make alot less power per pound of boost . If anything it feels like its making more or at the least the same. Tim at Bullet told me to just tun it up when i looked into a bigger cam . I think i know why he said that now. lol

[hgerhardt]

Imagine the power a Pontiac V8 could make if it could survive 11,250 RPM!

[Tom Vaught]

A "Modern head" would be a Overhead Camshaft 4 valve head like Mack McKeller came up with many years ago, (in the 60s). But because it wasn't a production head, "Can't do that". Course even the RA-V heads were not Production Heads, or the Aftermarket heads that look like a Hemi Head.

Run what you have Charlie, have fun, look for that good block, and ignore the comments from the cheering section that brags about a engine that does not resemble your 4 cylinder efforts.

Tom V.