S Sounds like a custom ground cam would be the best way to go in order to get the best bang for the buck. Unfortunately I can't afford to buy good aftermarket heads, this is why I'm looking at PSMSDR. I know that a closed chamber head is better for performance but the magnum heads are know for cracking. If I was to build a engine for a daily driver with a little extra zip what would be a good choice for cylinder heads? Am I limited to speedmaster cylinder heads or something like that?