Yeah the stock heads that came off the 92 had 5/8" holes for the pushrods. The rockers are in the same place as stock. I threw the stock set of rockers off the 92 onto the 71 head and had the same issue. The issue with drilling it out to 5/8" is the 92 5/8" hole is offset about 1/8 inch toward the rocker. I don't think I have enough metal to move the hole around that much.