I haven't had much luck searching. Does anybody know what is needed to remove the block drain on an '83 Jeep CJ7 258? It looks like a square drive, but 1/4" drive ratchet is too small, and even after sneaking a screwdriver in behind the header to scrape it out, a 3/8" drive doesn't seem to fit. Is it possibly a 5/16" drive, if there is such a thing? Or is it a hex drive(allen key), I can't really see it that well and I don't want to pull the header just for this. Any help is appreciated.