Sorry lol, i am going to be using it for street/strip in a camaro, Not sure what the cr will be in the end i was just told the pistons were rated for 10.5:1 cr and my heads are the 624 76cc heads also have a set of 882's. I just don't want to buy a cam that is too big for my set up because I'm not to knowledgeable when it comes to that. Also where i am i dont have to worry about smog laws or emmissions