C1 Oil Drain Plugs

[Art B.]

I was reviewing the '61-'62 Technical Judging Guide and noticed that the oil drain plug is supposed to be 7/8 hex. Both my '57 and '61 have 9/16 plugs. The '57 guide does not state a size. Is 7/8 correct for both '57 and '61 Corvettes?

[William C.]

Re: C1 Oil Drain Plugs

Looking at my old parts books, 57 used part number 3739264, shown as having a 13/16 head size. by '60, the description was the same but the part number was 3739264and that was the same as used in '65. I believe the judging guides tend to refer to it as a 7/8 hex, but in any event, the large hex would look to be what was specified for all the years in question.