'63 Differentials

[Ponchodon]

I am looking for info on '63 rear ends. Want to put a Richmond Power Trac posi system in my truck, but the factory stuff only lists the 8.2 inch, 10 bolt down to '64. What I am trying to find out, is the '63 any different than the '64? In my opinion, they shouldn't be, both have 6 lug wheels, etc. Anyone out there have any ideas???

[ruffrida2005]

63-64 is the same 17 spline 12 bolt rear. You may be better off getting a 65-69 rear as it's a 30 spline but the same lenght drum to drum as the 63-64. Someone else smarter then me should chime in though. but I think I'm pretty much right!

[Eagar1]

I believe they changed in 64 from 17 spline to 30 spline, and they are rare, is probably why no one makes a posi for it. I would think you would have to get the axles from a 64 to use with a richmond, but I am not sure they are the same length. It may be easier to just find a factory posi axle and bolt the whole thing in, as the 30 spline units were stronger.

[Captainfab]

Yes you are correct ruffrida2005. The '63 & '64 12 bolts (8.875 ring gear) have 17 spline axles. Starting in '65 GM switched to 30 spline axles.

I'm not familar with the Richmond Power Trac, but I would imagine it would be for 30 spline axles. If you can't or don't want to find a '65-'69 12 bolt differential, you can use your '63 housing with 30 spline replacement axles and the Richmond Power Trac.

Originally Posted by ruffrida2005

63-64 is the same 17 spline 12 bolt rear. You may be better off getting a 65-69 rear as it's a 30 spline but the same lenght drum to drum as the 63-64. Someone else smarter then me should chime in though. but I think I'm pretty much right!

[ruffrida2005]

Man I'm getting a little better at this being right part.