Need help IDing posi unit.

I believe is out of a 69 GS 400 with AC, 8.2 Buick. Can not find the code on it. Purchased the car and rear in 1991, Found and built the correct 3:42 8.2 for the car. This rear had GM 4.78 gears with spacer, and what appears to be a 2 pin/4 pinion HO posi, not sure, it does not look like a regular cone pose. Can someone help ID

 

It looks right. My guess is that it was originally a 3:42 or numerically lower posi,which is why the spacer was used.
Here are pictures of an original 3:42 and 3:64 posi unit for 68-70 Buick 8.2”.

 

Look on the bottom of the LH axle tube for a stamped code.

 

I did look but cannot make out enough of the code to tell what it was, thanks for the input. I did compare the posi to a 68/9 skylark 8.2 posi i have and it looks way different, that one has springs. and one pin.

 

Can you post or send pictures of the one your are trying to identify?

 

To use those 4:78’s without a spacer,you would need the carrier for 3:64-up. It is pictured on the left,above. It has that inner stepped circle in the inside of the ring gear bolt holes.

 

Meaning DRIVER side facing the ground. (sorry I hat e the left and right when describing the cars sides) LOL
1968 would be ( OO ) code posi 3.42
1969 would be ( MS or OO ) code posi 3.42.
Driver side axle tube facing the ground... between the spring perch and the cast center section.
Jim

 

I agree, I was first looking on the pass side. I found on bottom of drivers side, but cannot make out very well, will try to get picture and post.

 

Best picture I can get. if you blow the picture up it kinda looks like a N then a space and maybe a O or 097

 

“ON” is 3:64 posi,built the 97th day,which would be around April 7th. When was your car built?

 

Interesting, the 69 GS I thought it came out of was and AC car, so it must not original to the car. Did all 3:64 posi cars have the heavy duty 4 pinion 2 pin posi?

 

USAF and aircraft learned me left/right as looking from the back to font (or as one would sit in the aircraft).

But I use "driver/passenger" because it makes sense to everyone, except the Brits, and the Convicts in Upsidedownland. (but they are smart and can transpose)

 

3.64 carrier would not need a spacer for the ring....BUT if they totally BLEW up everything it still could be a 3.64 rear.

 

Exactly Jim. If that is an original 3:64 rear,my guess is they munched everything inside of it before,found a posi from another Buick rear and got the spacer. It has 4:78’s,so we know it wasn’t just taken out on Sunday for ice cream.

 

Thanks for the info, and help. Based on above, this is a 3:42 posi, with a spacer for the 4:78 gears. If it did not have a spacer would it be 3:64, 3:90, 4:78 and would not need a spacer?

 

Correct. Our guess is it was blown up at least once.

 

Thanks for the info, I am planning on selling it. What is a fair $ to ask for the complete rear end, with delivery to BG this year.

 

You just need the right person to want that steep gear. One of those pure stockers or FAST guys might want that.

 

Yep, There is always someone...lol. Jim