[Formulajones]

Originally Posted by Skip Fix

So if only 64-65 were shorter was the a "short" 12 bolt? I would thin GM/Chevy would not put a 12 bolt in since unless you got a rare 65 396 Chevelle would have just been a 283 or 327 in it.

What is the flange to flange length of short and "regular" length A body rears? I thought the "regulars" were the same width as second gen as the axles length is the same.

Yes there was a shorter 12 bolt that GM used up through 1967 A bodies. 68 they got wider to accommodate the new larger A-body.
Width was the same on the 12 bolts from 64-67 and they were installed in Abodies with the 327/300hp if optioned with 4 speed and the 327/350 hp Chevelles (all were 4 speeds) as well as all the 396 cars.

I have both versions here but I'd have to do some digging to get any measurements, they are stacked on top of each other like cord wood. I can tell you the width of the 68/72 A-body 12 bolts are exactly the same as 2nd gen 70-71 F-body 12 bolts, or 2nd gen 10 bolts for that matter. I have those versions here as well. I had to rob an axle from one of the 2nd gen F-body 12 bolts for my Chevelle 12 bolt one time when it had a bearing go south. Direct replacement.