I didn't build the engine so I don't know for sure what pistons were used. Runs fime on 93 pump gas with no ping/detonation. Has a racer Brown .510 hydraulic cam. Again I'm not looking for porting or max flow just want to clean up the transition from machined to cast surfaces and maybe smoothe the rough cast runners a bit. Everythung I read says aluminum heads want more compression so I don't anticipate any trouble with the closed chamber heads.
