Well Santone the valve jobs are simply put...excessive WEAR on both the valves and the head! The grinding thins out both for no reason. If the valves are working I never have seen a need to grind them down and have them seated deeper in the head.
When I have a burnt valve I get a new one and LAP it into position with a diamond compound.. JUST the one. Then I put the head back in service.
I have my own of course but I think you can BORROW a valve spring compressor from the parts house. It ain't rocket science!
Big JIm <img src="/forums/images/graemlins/pfft.gif" alt="" />