Guys:

Randy, I sure understand your approach and it will be a very interesting project regardless of the direction you ultimately take.

Turbo-6 and Tlowe, thanks for the info on the Brazilian head. Up to this point, I hadn't seen one and the ebay listing (along with Turbo-6's comments) was enlightening. It sure has some similarity to the 242/4.0L AMC/Jeep I6 head with the individual (and raised) intake ports.

I know this may be off the track a bit, but I ran across an old article from back in 1967 about an Explorer Scout project to build an altered roadster powered by a Pontiac OHC six. As I understand it, the Pontiac uses essentially the same block as the Chevy and the single overhead cam head uses the same 4-bolt configuration in some manner that doesn't affect the pairs of intake ports. The Pontiac head is a 12-Port design with individual intake ports which got me to wondering:

1. How well can these intake ports be made to flow?

2. Is there a good relationship between the flow of the intake and exhaust?

3. Would this head be a good starting point for a new Chevy head if you could replace the overhead cam with traditional rocker arms and push rods, and allow the use of the typical Chevy valve cover?

4. Are there any viable aftermarket intake manifolds available for this head so that additional development could be avoided?

5. Does the Pontiac's exhaust ports line up in the same location as the siamese port Chevy so exhaust manifolds would be useable?

Don't know if the Pontiac head has any real (or potential) advantages over the Brazilian configuration but it's at least another example of a 12-port design that has some commonality with the Chevy head. Interesting . . .

PS: After doing a little research, apparently the OHC exhaust port layout and bolts don't match the Chevy siamese port head. So that would be a potential issue.

FYI: At one point, a 24-valve DOHC aftermarket head was being developed for the Pontiac. Don't know what happened to the project but the prototype head (in progress) looked great.

Last edited by russk; 10/20/09 03:26 PM.