i used a spacer plate in my original turbo set up along with the head gasket.Spacer was about 2mm, never had a problem with blowing out the head gasket, i made sure it was a good qualitiy though. Stewart wilkinson motorsport sells 1mm nismo head gasket from memory.

What CR are you looking at achiveing? 8:1? 9:1?

you can run a higher CR with a better shaped chamber, than with a lower CR and a more poorly shaped chamber

Just get a custom thicker than normal head gasket made up. One mechanic I know says he has done it a couple of times with BMW's that has over skimmed or skimmed to max cylinder heads. He got gaskets then made up that are 1mm thicker than normal. His max so far is 3mm thicker than normal and the car is still running without blowing gasket. My brain is on the other hand telling me that it might blow head gasket easier in a turbo application where pressures are bigger.

what comp ratio are u after. what pistons are u using dish type if so what cc are they. a14 or a15 bore sizes/stroke. i may work out your head cc u need approx.

O lol now we feel like dumb asses. Well then just cc the head and check or use a deck plate type head gasket. Good luck

what size chamber are u chasing,by laying back a kidney shape chamber will increase cc volume and also make valve flow better.whats the reason your after a low comp head.

to to make you guys aware this is for a turbo setup so im actually after less compression.

A freind of mine who has tons of motors tells me that some of the A14 motors had greater volume dishes in the pistons. all in all, greater performance can be achieved from a combustion chamber with a smaller more compact design. it'd give better squish. i took and h72 head to a cyl head guru once. He told me i was wasting my time.

I know here in SA to get a gx head is almost imposible so I looked at ways to make a a14 head into a gx head and found the follow to be doable. Take 2.2mm off a standard a14 head and your combustion chamber is the same as the gx. Then you have to change your push rods accordingly. Or go to the guy who can fix a alu head of just some that does alu welding and ask then to fill the parts of the chamber you want to have changed. You then shape and cc to what you want. So if there is a will there is a way lol

Same with USA head. Last month i looked at a new in-box one, it was machined 5mm deep(?) for open chamber.



Virgin H72 head