When having cylinder head machining done and new valves will be installed, should the old valve seats be removed and replaced with new ones and angled to match the valves? I'm wondering if the new valves will be able to seat properly with the old seats even after machining. If they need to be replaced, does anyone know a source of supply? It's for a Z6 head. I checked Majestic but didn't see a listing for them. Thanks.

 

The machine shop will cut the seats (typically called a "valve job").There is no need to replace them under normal circumstances.