8.5 differential swap

Captain Beaumont · Poncho Master!

8.5 differential swap

4SPEED427 · A Poncho Legend!

You're talking about one that you can put in a 68 or are you trying to put a later diff in a 67?

As you know, the 8.5" to fit 68 to 72 A body likely only came in 72 Chevelles as determined by a thread here a while back. (At least I am hoping you recall that, it seems to me you where in on that one) Anyway, yes, you can just put the guts you have into a Chevelle 8.5" housing.

Captain Beaumont · Poncho Master!

Thanks yes putting it in a 67

rabbit64cs · Canadian Poncho Superstar!

can you put the 8.5 posi into your 8.2 housing ?

4SPEED427 · A Poncho Legend!

Captain Beaumont wrote:

Thanks yes putting it in a 67

From what I know, it's a bolt in, just a touch wider as I'm sure you are aware.

Only issue maybe the yoke on the diff. I suspect your 67 has outside snap rings, the 72 diff will have inside snap rings on the U-joint from what I recall. Simple cure with a conversion U-joint.

4SPEED427 · A Poncho Legend!

rabbit64cs wrote:

can you put the 8.5 posi into your 8.2 housing ?

Some say it works. I've never tried it, I hope someone with experience on this chimes in.

Captain Beaumont · Poncho Master!

Isn't the input shaft bigger on the 8.5

Beaumont4008 · Uber Guru

Captain Beaumont wrote:
Isn't the input shaft bigger on the 8.5

Yes you are correct. It is the same width as a 12 bolt pinion.

rabbit64cs · Canadian Poncho Superstar!

your just using the posi unit ..

I've read.. and heard from a car buddy that it has been done, he did it himself.

It's on my list of things to try .. I have a 8.2 camaro diff and a loose 8.5 posi.. just havn't gotten to mock up yet.

rabbit64cs · Canadian Poncho Superstar!

http://www.camaros.net/forums/archive/index.php/t-81296.html

L72/RS

May 10th, 06, 09:29 AM

The 8.5 r&p set won't fit, but an 8.5 posi unit can be used in an 8.2 rear.
We used to use them before Eaton released the newer 8.2 units, because the 8.5 units were much easy to find.
Later,
Eric

big gear head

May 10th, 06, 07:41 PM

I'll have to look into this one. I know that the ring gear bolts are not the same size. The 8.2 uses 3/8 bolts and the 8.5 uses 7/16 bolts. I haven't checked on any of the other dimentions.

L72/RS

May 11th, 06, 05:11 AM

BGH,
We used a thin wall DOM tubing from Victory Tube Products to make sleeves for the ring gear bolts.
I think the only other mod required was some of the castings needed to cleaned up for clearance on the passenger side of the case.
I will see if we still have one of the old setups on the rack and post a picture.
Later,
Eric

John65nova

May 11th, 06, 05:52 AM

Captain Beaumont · Poncho Master!

So the 8.5 input shaft probably won't fit in the 8.2 diff

hawkeye5766 · Canadian Poncho Superstar!

Nope, 8.5 carrier with 8.2 ring and pinion.

Captain Beaumont · Poncho Master!

Right, but that would delete the strength of the 8.5 upgrade, I would have a 8.2 posi but no added strength