New Dorman oil pan drain plug.  This is a double oversize repair bolt, also known as a piggyback bolt, which means it is used in place of damaged oil pan threads.   This is a slightly larger thread that will cut into damaged threads and become a tight fit in pans with existing 1/2"-20 thread.  Includes seal. Once installed you will use the smaller bolt to drain fluid in the future.  For slightly damaged threads, order a single oversize bolt instead.  Fits the following:

67-79 Firebird/Trans Am with 326/350/400/455 (Pontiac engine)

67-81 Camaro w/ 305/350 (Chevrolet engine)