[WillV]

So my son buys a posi rear end under the impression that it came out of a Buick GN 1986. He wanted to do a swap on his 86 Cutlass but came to find out its not a direct fit. The top arm mounts are spaced out 12 inches apart (approx) compared to his old rear end which is ten inches. Plus the shock absorber mounting area is at front rather then at the rear. I couldn't find any codes on the housing, but maybe these #s found on the gears might give a clue: 1113984825 45:41 974. Anyone have an idea what the rear end came out of? Thanks all for the anticipated help!

[Lightfoot]

I don't think any 78-87 A/G body rear ends used bolts to attatch the wheel cylinders.
Unless there was an acception for the GNX or something, they all had spring steel retainer clips.
Those drums don't look at all like the type used for 78-up A/G body anyway.

I'm trying to think of what would have had the rubber snubber. The 45:41 resembles the gear tooth stamp, but those numbers don't make sense unless you copied them down wrong (not saying you did ).

I'm guessing it came out of a 73-77 A body.

[WillV]

Yeah.. 45:41 doesn't make sense.. I'll take a peek again tomorrow. Thanks for your input.

[Mr Twister]

How wide is it, and how many bolts are on the cover?

[ponchbro]

I have a 87 GN rear end in my 78 Grand Am and it is a direct bolt in. The backing plates look like they are form an earlier car.

[WillV]

sorry, blame it on poor vision.. the ratio is 15:41

[Mr Twister]

Originally Posted by WillV

sorry, blame it on poor vision.. the ratio is 15:41

2.73 rear gear ratio