How much head milling = how much more compression?

timk225 said

I'm not asking what my current compression is (and 8.4 is what is listed in a 1973 Dodge shop manual, I know it is probably wrong). I am asking what the difference would be with a head sitting 0.060" lower. I know this number will vary some based on what the current actual measured compression is, but it should be a reasonably constant figure.

Something like a 0.060" head lowering should improve compression by roughly 0.3 or 0.6 or whatever.

Click to expand...

You're asking the same question. No one can know what the compression will be after milling, because no one knows what it is now. You must measure first to determine what your compression is now, in order to calculate what it will be after milling. THERE IS no magic answer other than you must measure. The reason is because each head will have slightly different chamber sizes, each engine will have slightly different deck clearances and so on. So you must measure to find out. Charlie came as close to an answer as anyone can by telling you "about" how many thousandths of an inch equals 1 cc. But you must STILL MEASURE in order to find out.