10 bolt compatability
 

i ahve a 72 lemans with a 8.2" 10 bolt in it now, im looking for a 8.5" unit. but which vehicles are donors for a complete bolt in unit ( besides gto's and lemans's obviously) and can the camaro axles be easliy modified to fit? are there any width issues with any of these?

Gm A bodies and why use a camaro axle in a 8.5? wrong length.

there jsut seem to be more camaro axles available with good ratios in them, so all A-bodies? is there any preference on the year, and are they all the same width with same mounting points?

Plenty of GM "A" bodies came with 12 bolt rear-ends which is even a step up from the 8.5. I think these are even easier to find than the 8.5. El Camino, Buick, Olds, etc. - plenty came with the 12 bolt. Years 68-72.

there's no bolt-in 8.5 rear end.
closest to a bolt in would be a rare one from a later g-body 442 or buick GN.
these are real hard to get and pricey.

In 71/72 both the Olds Cutlass and Buick Skylark came with the 8.5” rears. They are a direct replacement with the exception of a 1” drive shaft difference. Beware however that some of these cars did come with a BOP 10.2” too so don’t just assume, look at it and make sure it is what you want. The 1973 and on rears will not fit the 72 and earlier cars. Forget about the Firebird/Crow-marrow rears as they will not have the “ears” for the upper control arms needed for the a body cars.

Forgot to mention you may need a conversion u-joint to go from your current 1330 series to the 1310 series rear end yoke. Again check ahead of time to make this changeover easier.

Warped,
So the 1330 is the standard U-joint in the GTO/LeMans? Hard to find info on it.
Thanks.

i've never ever heard of those years' a-bods coming with a corporate axle.
very interesting.
thx for the info, i was obviously wrong about it.

About five years ago I didn’t know they existed either until I meet up with a few Buick guys at the local Saturday night burger-joint hang out. And they are not c clip axles which is a plus. And on the 1330/1310 u joints, they are commonly used Spicer part numbers for the large & small u joints and there is what some call a crazy joint that adapts a 1330 driveshaft to a 1310 rear yoke (or the other way around if needed). Every 64-72 a body I have ever seen have had the large (1330) joint but wouldn’t be surprised if there were some small (1310) one out there too...

Warped,
I have been trying to find information locally on the GM u joints & the more I looked, the more confusing it got.
From what I have learned, the A body takes the '3R' u joint, which has the same diameter caps [ 1.125" ] as the 1330 joint, but that is all. Where they differ is in the circlips. The 3R uses internal circlips & the 1330 uses external circlips. Unless you get a hybrid u joint that takes internal circlips, then it won't fit a standard A body yoke.