another j head question

63dartman,
You can do this and you shouldn't have any issues, but when cutting .060 off the deck surface then .072 will have to be machined off the intake side, or the intake manifold will have to be cut, but then this manifold will only fit the heads that they will be cut for. So your better off cutting the intake side of the heads as then they can be used on any engine and so can the intake maniflod. As for valve to piston clearence with the .480 cam. If the piston is at stock location they will be .080 to .105 in the hole, plus the thickness of the gasket and the recess of the valves in the head, by recess I'm talking about how far they are from the deck surface of the head to where they sit on the seat. So valve to piston clearence should be more than enough. I would be more worried about the retainer to guide clearence than valve to piston clearence. As stock guides wont take much more cam without hitting the top of the valve guide, so this needs to be checked. You need .100 clearence over the valve seal to be safe, or it has to be machined.
Stay with the small valves as they will be better for torque on the street and occasional racing.