70 GTO Rear axle question
 

Why is it that some 70 GTO's came with 10 bolt rears and some 12 bolts?

In 1970, only the 455 got the 12-bolt.

I have a friend that has a 70 GTO Judge RA III that has the 12 bolt. Its dated for the cars build. Pretty sure it came that way.
Is this possible? Any other known exceptions?

It’s possible, but not probable. Only the 455 HO was supposed to get the 12-bolt from the factory. The axle code should be one of the following:

3.31 ratio - WU: open carrier, XU: posi

3.55 ratio - WV: open carrier, XV: posi

It was either a 455 car from the factory or somebody put the 12-bolt in there. OR it is a very, very rare factory mistake, which would be impossible to document.

didnt all Oshawa Judges and GTOs for 70 get 12 bolts regardless of engine, because of the supplier location?

I know all the canadian built skylarks did, even if they had a 6 cylinder..i myself have removed 3 from 350 2bbl cars

Nope

No I’ve owned several of them and a friend of mine still has an original silver 70 judge all 10 bolt and all oshawa build cars

humph....new lesson for me...

What if the 3.55 was specified buy the customer? Then it would have to be the 12 bolt.