Originally Posted by Tmurph2960
.004 to .006. You will need a hex wrench set, feeler gauge, and a socket set. Turn the engine over until you have it at top dead center. Both valves should be closed and the piston at the top of its stroke. Check your gap then and if it is greater than .006 then adjust.
Murph....you're a little confused....FB460 engines are different than FC420's....
You have to remove the head and remove the valves....then grind the valve stems to get your clearances on the FB460.