It is good to see you are having your rotating balanced. I was wondering if you talked to a machinist about using closed chamber pistons with the open chambered heads. I have heard it reduces flame travel so try and keep your quench as close to .040 as possible. If your block has not been decked then the pistons are .020-.025 in the hole at TDC. This makes having a quench of 040 impossible. On my 454 block I had it decked to .005 and use .036 head gaskets. The Comp Cam you chose should work just fine. Don't forget to check your valve to piston clearance.