valve lapping...and heads

Lapping is the final step when the seats are re-finished. Old equipment needs them lapped in. The good equipment doesnt. You should not be trying to remove any pits. If there was a seat that was so bad it had carbon scaring all the way accross the margine (the exact spot the valve face meets the valve seat when it's closed) then it should have gotten the seat re-ground to fix it. So be careful. Lapping is not a repair operation but rather a final seating procedure whent the valve seats are marginal but ok.