Oil Pressure Gage and Sending Unit Revisited

I had a 79 300, which read low oil pressure on dash gauge. It kinda scared me, so I thought I'd screw in a mechanical fitting and check it. Never got that far, because when I pulled the electric sender out of the block, I could see a hanging booger of Teflon tape was covering the hole in the sender like a little flappy check valve. If you insist on using Teflon tape, hold it back a few threads from the bottom of the fitting, so it doesn't get in the way.