the top, I wouldn't use it. Sometimes, they stop turning and the cam will wear one strip of the top of the lifter instead of the whole thing. I haven't looked at the lifter FAQ in a long time, but you are resurfacing the tops of the lifters, right? Again, this might be in the FAQ, but I place a sheet of fine emery cloth on a flat hard surface and run the top of the disassembled lifter over it until the surface is uniform. Make sure you clean the metal that came off out of the lifter body before reassembling it.