65/66 full size 12 bolt posi rear end kijiji Guelph

norontcan · Canadian Poncho Superstar!

65/66 full size 12 bolt posi rear end kijiji Guelph

427carl · A Poncho Legend!

Nice stuff . getting harder and harder to find .

forespeed · Poncho Master!

These are getting hard to find. Lots of 12 bolt B body differentials out there but most of them are 2 series gears. They put a lot of BB in Impala and Caprice cars, not for 1/4 mile performance but highway cruising. These 2:56 and 2:73 geared differentials can't be upgraded to 3 series gears. The rearend shown here is from a Impala SS or BB performance optioned car.

The only problem with this one is no control arms. I was able to find one for my 66 Biscayne with the control arms still intact. That saved me about $600-800 for aftermarket control arms. The one shown also is a 4 link, as mine is, compared to the standard 3 link setup.

I also got good axles. The posi and all internal parts that I will need are not cheap but you need to start with the correct differential to make it all work.

seventy2plus2 · Canadian Poncho Superstar!

forespeed wrote:
These 2:56 and 2:73 geared differentials can't be upgraded to 3 series gears.

Why can't they be upgraded? I thought you'd just need to buy a 3 series carrier.

65 SD L79 · Canadian Poncho Superstar!

seventy2plus2 wrote:
forespeed wrote:
These 2:56 and 2:73 geared differentials can't be upgraded to 3 series gears.

Why can't they be upgraded? I thought you'd just need to buy a 3 series carrier.

that's what my thoughts were too

dcneric · Poncho Master!

So how are the 65/66 rear axles different than 67/68 & 69/70? I know the control arms differ as different bushings are used but I thought the 12 bolt housing was the same.

2drpost · Uber Guru

same housing 65-70

65-66 upper arms are a different length than the 67-70 arms

use any gear you wish, change the carrier to 3 or 4 series

cdnpont · Canadian Poncho Superstar!

I did a 3:55 in my 2.73 housing using an Eaton 3 series Posi. The housings are all the same, other than perhaps the exclusion of the 4th arm mount.

At first it seems a tall price for a 12 bolt, but try to recreate one from scratch. I probably have 2 grand into mine all said and done, and I already had the housing.

That is a very fair price.

4SPEED427 · A Poncho Legend!

Agreed. If that is the difference you plan to use, and plan to buy the parts to assemble it, this is priced fairly.

forespeed · Poncho Master!

That is correct, my intention was just to point out that you could not simply change the R&P. Also, I suppose you could add the bracket for the 2nd upper control arm. I wanted my car to be equipped with the OEM 12 bolt with 4 control arms that it would have gotten had it been ordered with the HP equipment from the factory.

Over almost a one year period of time, I searched online including eBay, craigslist and anyplace else I could find for a complete OEM 12 bolt differential with a 3 series carrier and 4 link brackets and arms. I found bare housings, differentials that were still in SS parts cars where it would be necessary to buy the entire car and OEM 12 bolt differentials with a 2 series carrier and gear set. For some reason, every time I found one that was completely rebuilt, the seller had removed the upper brackets and also some lowers.

The one I bought was the only one I could find original and complete with all parts. It was over 300 miles from home and the seller would not ship it.

Sorry for any confusion I caused

2drpost · Uber Guru

no confusion Norm, knew what you meant wink

don't believe i've ever seen a 65-70 12 bolt without the 2 upper arm brackets