I see a mis-match here. With flat-top pistons, 76 cc heads and assuming zero deck and a 0.039" gasket, your compression ratio will be 9.05:1. If you didn't pay attention to the deck height when you built the motor, I'm betting the piston is somewhere between 0.020" and 0.040" down in the bore at TDC. 0.040" in the hole would put your compression ratio at 8.3:1 This cam (rough idle, 2,800 to 6,000) is designed to work with 9.5 up to 11.0 to 1 and will bleed off most of your already low compression, resulting in poor power. In my humble opinion, you've started with the wrong heads for what you want to do (too much volume).
I saw last night on fb about John. The world sure lost a great one. I'm going to miss his humor, advice, and perspective from another portion of the world. Rest in Peace Johnboy.
John Norton aka johnboy