Josh,
I used one of the rear ports in the oil galley, above the starter. The oil galley is full size from front to rear on these engines. The oil pump is a direct port to the galley with the oil filter in the middle.
I have seen on some engines when taking apart, crud buildup behind a pipeplug. When you pull the plug, the crud will be like a wall. Kinda like plaque in a artery.
Maybe pull your oil line and crank once without it. The oil pressure should be very obvious. Likely squirting out.