1973 12 bolt rear identity???

[Doug Hopkins]

I recently acquired a 12 bolt posi and 2.93 gearset.The guy I got it from,said it came from a full size Pontiac.The posi has a date code of E253 May 25,1973.It also has a cast #250 on it.This posi has 31 spline axle side gears,and the pinion gear has 30 splines.Do any of you know what this will fit?? Thanks,Doug

[Doug Hopkins]

I recently acquired a 12 bolt posi and 2.93 gearset.The guy I got it from,said it came from a full size Pontiac.The posi has a date code of E253 May 25,1973.It also has a cast #250 on it.This posi has 31 spline axle side gears,and the pinion gear has 30 splines.Do any of you know what this will fit?? Thanks,Doug

[Michael Farich]

Doug,
My '73 Catalina came with 2.93 posi. I never read the codes on it, but I think the '71 thru '76 big Pontiac, Olds and Buick B body rears all interchange so looking under any one of those should help you determine if the rear you got is one of those. It is generally referred to as the 8.5" 10-bolt. Some big Buick C bodies, like Electra, had the same rear also. '76 is like that. These rears measure 59" from backing plate to backing plate at the outer diameter of the plate and at the outboard edge of the plate, I think. Some other big C body Buick and Olds like Delta 98 and Electra had a different rear. These are not the 8.5" 10-bolt but will probably bolt in to any '71 thru '76 big Buick, Olds, Pontiac. I'm not sure if Chevy Caprice is included in the interchangeability or not. Probably is, though, because it is a B-body.
Mike

[Doug Hopkins]

Michael,This is what I have,just the posi and gears.Thanks,Doug