In Reply to: From a 1959 dealer parts book posted by Ed Gooding (VA) on February 07, 2023 at 05:34:16:
Well, I dug into the tractor more yesterday and found what the hole was for. There is a square pin (or something similar to a pin) underneath the air vent hole in the valve cover. It aligns perfectly with the square hole in the gasket. So the hole goes to the bottom.