Oil Pressure

There is a plug in the oil galley that almost always gets left out at the rear main at rebuilds. It could be this, it pumps oil right back into the pan. If I remember right if you remove your oil sending unit and put a peace of 1/8" gas welding rod or wire down the hole it should hit the plug at 7 1/2" - 7 11/16" if not you will have to remove your rear main cap and install it. It is a press in plug like a shot plug and goes in 2 1/8" - 2 5/16" in from the bottom of the block. Make sure you use a stud locker loctite so it can't come loose.