Can't zoom in on your pic enough to see what you're talking about. Can you post a closeup of the area where the plug is? Possibly someone removed a freeze plug and threaded it for a pipe plug, but can't tell from your pic.
Kevin 1951 Chevy 3100 work truck Follow this saga in Project Journal Photos 1929 Ford pickup restored from the ground up. | 1929 Ford Special Coupe (First car) Busting rust since the mid-60's If you're smart enough to take it apart, you darn well better be smart enough to put it back together.
