I see someone disagrees with this statement. Not sure why. If we're talking about the fill plug on the differential cover of a 7 1/4 rear end, that may look to modern eyes like it takes a Torx fitting, but it's not. To my knowledge Torx wrenches didn't even exist in 65. At any rate, the half inch drive of a ratchet wrench is what I have used many times, and I found a You Tube video that shows how a half inch drive (in the video, of a breaker bar) fits the plug perfectly.
An 8 3/4 rear has a fill plug on the passenger side of the chunk. That plug takes a 5/8 open end wrench.
