just wondering if anybody knows if the h72 head is actually a low comp head. The wiki says its not but i thought any of the 360 degree chamber heads are low comp.

The compression ratio is two parts: CCs of combustion chamber (cylinder head) and CCs of piston dish (in pistons).

The H72 as used in USA with dished pistons is medium compression ratio. But the CC of the head isn't extremely large.

H72 is also a casting number. There may be several different heads made from H72 casting.

FWIW my "dry" Jap import A14 H72 head has a 2.5mm deep x 76mm diameter counterbore.

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

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

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.

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

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.

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 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.