Those are possibly not Stage III heads Max Wedge heads. "516" are a mid 60's, closed chamber run of the mill heads found on 361's, 383', maybe 413's and possibly some 66-67 440's. They have 2.08 intake and 1.60" valves. There are better stock B/RB heads but it depends on what your doing with the 440.
"518" Stage III Max Wedge heads are a whole other deal. Got a picture of the ports and the whole head?
