Yes, just plane. Some of the 216s had no cap on the valve cover. They all had a hole in the block by the distributer for a breather/oil filler. Little Offey style or your side mount breathers would be a clean setup. You could cast in the boss and machine them if the customer wanted. Someone else also makes and adapter to put this old style cover on the 194-292 engines. I doubt if I'll ever run one of these engines again with all the Jimmys, 292s and 153s piled around here.