So I’ve double checked my deck height with a clear head and the measured height is .031 below the deck. This is with the kB 162 and their 1.908 listed CH. My head gasket is .039 fel pro with a 4.490 bore. My biggest problem is with the heads I am stuck with. They are 452 with a 92cc chamber. The best piston I can find is the speed pro forged L2315F with a 1.920 CH. that should make my deck height a .019 now. My phone is almost dead so I can’t run these through the website calculators right now. I may calculate by hand later tonight. the 70 service manual list two different CR of 8.7 and 9.5. I bet they don’t make the 9.5 piston anymore.
going to a steel shim gasket will take out 4cc's. milling .030" off the heads will take out another 5-6cc's. real issue may be pump gas or gas blends. camshaft will dictate some of this. for pump gas driver i'd stay around 9-9.25:1 compression ratio. kb says 8.6:1 with those pistons, 90cc chambers, and .040 gasket. I wouldn't change the pistons. 9:1 is easy to get to. just make sure the end gaps are correct and work with what you have.
