what cam??

I'd stick the MP .528 solid in it (budget choice), the Comp XE268H, or the Lunati 60302. The Lunati will need a psring upgrade, and I'd reaplce the retainers and locks if you didnt when you got the heads.
Lose the thought of "12:1" pistons. If you want to properly rebuild it to run hard on pump swill, then do it. It won't use "12:1" pistons.