Hi, I am sure this has been talked about before, can anyone guide me to where on this forum if possible? I can't seem to locate the information. The question is about how much to mill the head surfaces and inlet (intake) manifold for, say, one point extra CR. Is there a rule for LA engines that says, if you mill the heads this much, you will get this much CR increase? Also, if I mill the heads say 25 thou, is it also 25 thou off each intake surface? Or something different? My engine (273) is approx 8.5:1. I want to go to about 9.5:1. No other option is available for me at this time. My question is, what is the rule for this? What amount taken off the heads of an LA engine (in my case, a 273) will produce approx 1.0 point increase of compression? And what is corresponding amount required to take off the intake surfaces? Thanks!!