Once in a while, we have to machine up valve seats for knuckleheads. The seat on the left is a blank, and the one on the right is one that my dad cut the od and id down on. This is a good fix, but you have to remember to check to make sure that the bore that it presses into is concentric, other wise it will drop out when the head gets hot!
After we make each valve seat to spec, we throw them in the freezer for a couple of hours. I found a dead mouse in the freezer, which is really bizzare. I think that Mara put it in there. I am not sure though.