I have another Question: I want to get my motor 340 back to 10to1 comp. is the 70 340 pistons different from my 73 ones and will they give me my desired net of 10to1?
Pistons will do the trick with a pair of the large port/large valve, open chamber, 340 heads. (or performance aluminum.) You can also build a flat top piston engine with closed chamber aluminum heads.