Just a thought looking in the classified's, ltman has a set of G heads for sale and it has the marking like one of the sets I have which were cast in Dearborn (the ECZ-G is in a small tag on the casting) vs the Cleveland having large casting letters with no tag. also the Dearborn ones I have the tags are upside down.The question is does anybody know how many were cast at each facility and are there any differences in them?