As a point of interest, a 2.30 intake valve will hit a 4.375 bore at a little over .800" lift.
Doesn't surprise me, 2.30 valve is pretty big and 4.375 is kind of small for an engine that needs a 2.30 valve. Typically you would want a 4.500 bore for that big of a valve. It might not pay to put a 2.300 valve in a head if the bore size is only 4.375.
