How to tell the difference between A body and G body rear ends

I know how that the GM A body and G body rear ends “look” very similar, but what is the actual difference??
Thanks
Gary G

 

73-77 is a wider axle
78-87 is narrower than 68-72....don't quote me on this, but pretty sure.

 

Housing width shouldn’t matter, my guess is that the lower control arm mounts are either way narrower or wider, and the coil spring perch is in a different location too.. All similar but different, I know they are not interchangeable.....

 

You can put an Abody rear in a Gbody, takes offset upper arms, couple easy ways,.. Gbody rears have small axle tubes, the have a bubble there where the shock attaches, and they have small bolts going thru the backing plate, because they are c clip,..our Abody rear have the oval head bolts with the nuts inside the backing plate

 

I think g bodys have 1 shock mount on the front side of the axle tube and 1 on rear.....but I'm going from my memory here and just ask my wife, it's wrong alot

 

Should be easy to see the g-body rear will be the 7.5" unit. Smaller all the way around

 

The 8.5 Gbody rears have a similar size and appearance center section but that's where it stops

 

Rats! I thought we were talking about gurlz!
“Yeh,(yawn) she does kinda have a body”
“Hubba hubba! Gee! That’s some body!”

 

Q: who laughed at your A-body / G-body joke?

A: No-body.

 

Lol “No-body” I love it lol

 

I swapped an 81 Cutlass rear into my 67 skylark. The differences I found were as follows:

A body spring perches in front of axle.
Brake hose goes center of frame to center of differential

G body perches on top off axle. Brake hose goes from driver's side of frame to driver's side of differential.

I cut off and swapped spring perches and made new hard brake lines on the rear to line up with the center diff.

I only know this because way back in my younger days, I did the same swap without paying attention. I didn't notice the spring perch issue right away, but the brake hose issue was pretty obvious. Being young, dumb and not knowing about making new brake lines, I had front brakes only.

I found out about the spring perches after a week or so, the rear shocks stopped dampening. Curious, I crawled under the car to find that when the springs compress, they also bend backwards, pushing on the shocks, until they popped.

The upside, the g body rear was 4 inches narrower and allowed a more common offset for a rim in the rear without ordering custom wheels.

-Josh

 

Thanks Josh. I thought there was something with the spring perches, I welded some onto a housing for my buddy... Way back in the day....