johntorg

Not exactly a turbo question: I have a good 968 shortblock and am investigating installing a 2.7L head, bur leaving the stock pistons. I know this is done to make a 3.0L turbo, with lower compression pistons.

I am looking at going NA and using the engine in a NASA GTS2 race Car. If its feasible, it should make a "torque monster". I have the following questions:

Has anyone done this?

What will be the resulting Compression Ratio?

Are there any valve clearance issues?

Mark944na86

Why would replacing a 16V head with an 8V head give you a "torque monster"?

johntorg

Just more torque compared to an 8V 2.5 or 2.7

C ANDERSON

MAY HAVE VALVE RELIEF ISSUES

johntorg

How can I confirm this? I assume the pistons can be notched for clearance. Still need tot know if the Compression Ratio will be OK.

fast951

Using the 2.7L head with the stock 16V pistons will lower your CR to around 9:1.
By using the stock 16V pistons, you are making too many compromises. It's best to get proper pistons for the application.

johntorg

Thanks John. Are you certain of the 9-1 figure? I guess at 9 to 1 I could just turbocharge it and have another 3.0 L turbo. I have a couple of 16V S2 engines and I guess I could use either one of them or use the S2 Head on the 968 block.

Mark944na86

If you are going to stay NA, I would have thought this is a more logical approach... cheaper and better results.