>>>*Lapping is something we do as a final check to fit, and then only very lightly. A properly machined fresh seat will lap itself in operation as the valve rotates when running.

One thing to remember is checking the fit. We use a wide black marker pencil and coat the valve face. Press it against the seat and rotate the valve 1/4 turn back and forth to create a mark.

It is important to not rotate completely when checking, or any high spot on the seat will create a nice even circle in the paint marker.

Set the valve in the guide, use a short piece of 5/16ths ID rubber hose over the stem of the valve, this helps give a good grip for lapping if you don't have a lapping stick handy.

A lapping stick is just a short shaft with a suction cup on the end, those kinda sorta work, I like my rubber hose trick better.

If you get a clear thin mark 360 degrees on the valve face, good to go. If the mark is very wide, have the seats recut.....*EB