I destroyed a new rebuilt Ford 302 engine due to this plug blowing out during the break in run. Now, I request all galley plugs be threaded, maybe some minor leakage, but not a blowout.
I had the same plug blow out on my new rebuild 5.0. Was using drill to turn the pump and something told me to remove the passenger valve cover and see if oil was getting to that side. Tried starting it before hand, heard crunching sound. Pulled pan off and there was the brass plug chewed up by timing chain. Put a steel one in and been ok for 16,000 miles so far.
See the little indentations around the edge of the plugs, they are supposed to keep them from pushing out.
I'm not sure I think it was like that when I originally pulled it from the donor vehicle machine shop told me to take a chisel wider than the whole and "stake" it two different ways like a cross and use anaerobic gasket maker on them
