valve shim thickness for worn valves

[JACK STRAW]

we are new to 450s so is there a valve shim thickness that determines that the valves are getting "sharp" or the seats are getting worn, instead of pulling the head
thanks

[blacknblue#2]

If I'm thinking right the smallest shim in a hot cams shim kit is 1.2mm which is about .050 of an inch. When you get down to that point your valves are pretty well shot