If you don’t change the combustion chamber the milling given below will give a reasonably accurate estimate of CR using stock pistons, bore and stroke and a stock head gasket.
If you enlarge the combustion chamber by a multi-angle valve job or polishing you may need to mill the head a bit more. 'CC’ing each combustion chamber to make sure each is close to the same size is advised.
- Mill (in) CR -
-0.018 10.0 (Mill the head ~18 thousands to raise the CR to 10.0 to 1)
-0.026 10.2
-0.034 10.4
-0.038 10.5
-0.042 10.6
-0.049 10.8
-0.056 11.0
-0.060 11.1
-0.063 11.2
-0.066 11.3
-0.070 11.4