A friend and I were discussing the other day what upper alternator Bracket is Correct for a 1970 Z28.
The GM parts book shows part # 3932410 as fitting 1969 and 1970.
1971-1974 is 3973396.
The reason I am asking is I know that 1969 brackets do not have the extra big hole that is common on 1971-1974 Camaros.
He has the upper bracket WITH the extra big hole and he swears it is original to the car, it is a 02A. I am thinking that someone must have swapped it out before, considering the GM parts book shows 69-70 as the same.
Does any TC member know for sure?
Thanks in Advance.

Any parts book after 1969 will show superceded parts for the 69. 69 is no hole, 70 has a round (around 1 1/4 inch) hole. Too bad I cant post pictures.

Hi Jon, Thanks for the reply, that is appreciated. Yes I am aware of the superceded numbers, my parts book shows the original number as #3932410 for both 1969 and 1970, with the part#6262956 being a later issue number for 1969-1974.
It also shows the original part#3973996 as being for 1971-1974.
My friends 1970 Z28 has the bracket with the big hole, it is a 20,000mile car, but I can not confirm that the bracket is the 1 the car was born with.
I have a 6,000 mile complete 1970 Z28 engine carb to pan that has been discussed heavily on Yenko.net, complete with the block chalk marks and ink stamps on carb etc, and interestingly enough it has the upper Bracket with no hole. Pad reads V0707CTB by the way. I can not confirm also if this bracket was born with this engine but it sure looks original, the rest of the engine assembly is unmolested.
Perhaps GM used the no hole bracket until assembly plant inventory ran out?
The mystery continues.

Not that I know much about '70s but the March 1970 Hot Rod test Z28 has an alt bracket with 2 round holes; a small one just under the battery cable ground and a larger one maybe 2" away. Probably a pilot build.

Doesn't the '70 also have the clip for the ground wire?