Found this funny Look for it

 

12 bolt (10 bolt cover)

 

Yeah, someday people will stop using the "10 bolt" and "12 bolt" designation for non-Chevy axles.

Well, I can dream, can't I?

 

LOL Joe , Yes... it surely is NOT a simple topic.

 

Posi for big cars?

 

At first I half thought so as 65-70, 71-76 Pont/Olds except this is 28 spline not 31 . It's maybe 77 up big car BOP

 

I'm going with that.

http://www.ebay.com/itm/1977-82-Buic...-/171421714312

 

Really?


There is a
12-bolt cover, 10-bolt ring gear


and


10-bolt cover, 12-bolt ring gear


version?


In addition to the only Joe-approved termed "12-bolt" -
C type 12-bolt cover, 12-bolt ring gear...


???

 

Yes, really. Used on the full size cars. 9.3" ring gear. Nearly bulletproof, if you could get parts for it.

 

besdies the 57-64 9.3 Olds/Pont , the 65-70 Pont one is 8.875 but there was a 9.3 Buick one I have seen posi ones in like a 69 Wildcat 430 it was huge