[Rick Parker]

dynoroom has mad a very valid point. Not only do you need the stones but the rotary power tool, and the diamond stone dresser. It is an aquired talent to do a nice set of seats in a head and have them all the same depth. You can screw up an otherwise good set of heads pretty quickly, the stones can chatter and cause a lot of damage and before you know it you have sunk the seats into the head and they are too wide. Leave it to the pro's that do it daily.