These pistons will fit the Y7, Y8, and Z6 heads - compression height is 29.97mm (1.180") dome volume for 13.5:1 (max compression) is approximately +6cc ** for 12.5:1 is ~+3.5cc - both based on a .030" gaskets -
For the A6 heads we don't offer a shelf piston, but can make them for you either for all motor or turbo configurations.
