Don Terrill’s Speed-Talk

I'm about to begin working on a Pontiac Super Duty 4-cyl. engine that is ~ 4" bore x 3.250" stroke. Due to lack of parts availability, and poor on-track competetiveness, the sanctioning body may allow us to replace the "801" raised port head with a current V-8 head. What would be required to use a V-8 head on one of these GM Performance Super Duty blocks? I've been told that the head is fastened differently on the 4-cylinder. Not sure if that means different size studs, or a different pattern? Both engines have 4.400" bore spacing, and I don't mind doing machining, as long as the result is a durable fix...

Looking towards either an 18deg. or 15deg. head if it's feasible. Intake manifold and header changes are expected.

Thanks,

Contact Dan Barton on here

KRP, Kansas Racing Products, owns the molds. They still have the GM number, but beefed up. The cool thing is they will drill the deck for ANY SB cylinder head. Chevy, Mopar, Ford, any of them. It's a good block, I built one with a SB2.2 head and 3.750 stroke.

cspeier wrote:KRP, Kansas Racing Products, owns the molds. They still have the GM number, but beefed up. The cool thing is they will drill the deck for ANY SB cylinder head. Chevy, Mopar, Ford, any of them. It's a good block, I built one with a SB2.2 head and 3.750 stroke.

That sounds like a very good idea. I believe Toyota did a midget engine a few years ago with a Craftsman Truck Series head.

Jon

I had assembled a few Pontiac 3.0 liter engines for a road racing effort that used the Cosworth 16 valve heads.
Dyno sheets showed 405 hp@8000 rpm NA. Fantastic looking castings. Engine sounded great too.
We used the Cosworth EFI computer, and 2 fuel injectors per cylinder.

We also put one of these Pontiac/Cosworth engines in a datsun 510 for ice racing

OldSStroker wrote:

cspeier wrote:KRP, Kansas Racing Products, owns the molds. They still have the GM number, but beefed up. The cool thing is they will drill the deck for ANY SB cylinder head. Chevy, Mopar, Ford, any of them. It's a good block, I built one with a SB2.2 head and 3.750 stroke.

That sounds like a very good idea. I believe Toyota did a midget engine a few years ago with a Craftsman Truck Series head.

Jon

It purred like a kitten but at 10K things were getting stupid crazy! It was fun while it lasted. Make good power, would have made more if I would have given it more time. However when your index looses .18 in 7 months, it's time to bail.. So I bailed..

I also built one ( KRP block) and SB2 head for a Bonneville car. Also purrs to 10k or so (even 12-13 once when came out of gear- oops!) Anyway, the stock SD4 uses a 4 bolt head pattern and is different from the SBC. KRP with new blocks can drill anything as Chad said. I don't know if that can be done with a stock block but don't see why couldn't weld/seal up the stock holes and redrill for the SBC. Sky is the limit head wise then. The KRP blocks are now $3500 bare though. I had thought that the 801 head could be prepped to flow pretty well (275 intake IIRC) that should work pretty well on a smaller engine with statement from GM enough to support 275+hp anyway. Check their website.

http://www.kansasracingproducts.com/Kan ... lcome.html

While back with GM help, Hot Rod put out a book called Pontiac Performance Plus that was about building the Fiero SD4 road race car that was pretty successful late 80's and also had a guide for building the SD engine with lots of machining tips, prep guide etc. See if you can find one on Ebay or used books or something. I have one in PDF format in a (very) old computer but have not been able to get it out to email or anything. If you can't come up with one, I can try to cobble a printer and see if can print it out and would be happy to send to you.

The 4 valve Cosworth head mod did make good power and I looked at but they are few and far between. Reported 500hp in Camel Light trim.(3 liter) Have seen occ complete engine for sale but I doubt that would be legal for you.

This may be the download you are looking for. It's 14+ mb.


http://www.fieronews.net/fusion/Downloa ... 4guide.pdf


Jon

I personally travelled to Torrance Ca. and picked up all of the Cosworth Pontiac cylinder heads, pistons, cams, fuel rails, etc. including 2 complete IMSA spec Camel Light 3 liter engines. Cosworth was emptying thier warehouse at the time - It was in 1990 I believe.
There are some of these parts left. Some of the 16 valve head kits were sold yo a drag racer in Puerto Rico a few years back. He was trying
to make 1000+ HP turbocharged.

jacksoni wrote:
I had thought that the 801 head could be prepped to flow pretty well (275 intake IIRC) that should work pretty well on a smaller engine with statement from GM enough to support 275+hp anyway. Check their website.

Here's the chart for my head, which is a mildly ported 433 casting. The peak was around 270cfm, 801 should be be much better.

http://img.photobucket.com/albums/v87/F ... adFlow.jpg
http://img.photobucket.com/albums/v87/F ... CF1269.jpg

Putting an SB head on a stock SD-4 block presents a challenge that's sometimes overlooked, the lifter bore locations and angle.

A couple of years ago I bought one of the Cosworth Pontiac heads. I've been trying to find the cams and front timing assembly for it ever since. I haven't had it flowbenched yet, but I've been aching to see some semi-definitive numbers out of one of these for years. Been working on intake and exhaust flanges and other little bits while I wait.

http://img.photobucket.com/albums/v87/F ... CF1301.jpg



http://www.fiero.nl/forum/Forum3/HTML/000020.html

JoeBlow wrote:

jacksoni wrote:
I had thought that the 801 head could be prepped to flow pretty well (275 intake IIRC) that should work pretty well on a smaller engine with statement from GM enough to support 275+hp anyway. Check their website.

Here's the chart for my head, which is a mildly ported 433 casting. The peak was around 270cfm, 801 should be be much better.

http://img.photobucket.com/albums/v87/F ... adFlow.jpg
http://img.photobucket.com/albums/v87/F ... CF1269.jpg

Putting an SB head on a stock SD-4 block presents a challenge that's sometimes overlooked, the lifter bore locations and angle.

A couple of years ago I bought one of the Cosworth Pontiac heads. I've been trying to find the cams and front timing assembly for it ever since. I haven't had it flowbenched yet, but I've been aching to see some semi-definitive numbers out of one of these for years. Been working on intake and exhaust flanges and other little bits while I wait.

http://img.photobucket.com/albums/v87/F ... CF1301.jpg



http://www.fiero.nl/forum/Forum3/HTML/000020.html

Looks like Canada1 might be a resource to complete your 4 valve.
My block is machined for the SB2 lifter locations/angle. Have seen several stock SD4 as well as KRP blocks with standard lifter bores with no issue I am aware of but bow to your experience on that point. Certainly in any hybrid like this all machining must be checked for compatibility. My head flows 383 at 850 lift so you can go up if you want.

I worked for Cosworth in the UK & built some of the first batch of these engines some of which were sent to the USA the remainder were sent as kits. This was way back in the late 80’s, If you were to Contact Mahle Powertrain Ltd in the uk they was formally Cosworth Engineerings road engines department they my be able to help with drawings & technical details, worth a try.