NA 170 street motor has 9.5 CR (which is too high for the cam I am running. Had to do a lot of distributor work).
170 turbo motor has head with just a "cleanup/truing" cut and a .080 thick head gasket (7.9 CR)
Nitrous 170 and 225 motors both have approx .125 milled off the head (38cc chambers)
