rear end recognition

[cyrus_the_great]

i was looking for a Abody 64`72 rear end then one of junkyard guys called me with a size about backing plate to backing plate 54.25" and 10 bolts on cover and coil spring , that 's only info what i could get from him and no photo too ... so what can it be ? 8.2?8.5?

1.as i know all 12bolts were 8.8"
2.BP to BP on 7.5 rear end is 52.75

so my guess is about 8.2" rear end because of BP to BP distance .. i am not sure if a GM 8.5" rear end before 72 could be with 54.24" between two BPs .

let me know your guesses please.

EDIT , got pictures...

 

[ssn696]

That looks like a Caprice/Impala 8.5" axle. The upper control arm mounts are lower and wider apart that the G-body pattern, and so, sadly, you will have a hard time making this work. The 10-bolt Olds/Pontiac one with the 'scallops' in the cover might be closer i you can fabricate a bracket to hold upper mounts. The McLaren GNX modifications ditched the upper control arms and used a special aluminum differential cover that had arms top and bottom for a traction bar plus a Panhard bar. I always wondered whether I could make a thick plate that sandwiches between the cover and housing, use longer studs in place of the cover bolts, and make control arm mounts with a 45 degree twist out of the top of this plate to fit the upper bushings. Using spherical rod end upper arms might also enable this scheme to work.

 

[cyrus_the_great]

That looks like a Caprice/Impala 8.5" axle. The upper control arm mounts are lower and wider apart that the G-body pattern, and so, sadly, you will have a hard time making this work. The 10-bolt Olds/Pontiac one with the 'scallops' in the cover might be closer i you can fabricate a bracket to hold upper mounts. The McLaren GNX modifications ditched the upper control arms and used a special aluminum differential cover that had arms top and bottom for a traction bar plus a Panhard bar. I always wondered whether I could make a thick plate that sandwiches between the cover and housing, use longer studs in place of the cover bolts, and make control arm mounts with a 45 degree twist out of the top of this plate to fit the upper bushings. Using spherical rod end upper arms might also enable this scheme to work.

tnx for your good idea , but none of rear ends of caprice/impala can have 54.25" for BP to BP size ...i think that 's rear end from 64-72 abody cars and UCA angle look like before 1972 abodies

abody UCA angle

 

[Rick_B_86]

I'd say it's an 8.5 (the triangles in the corner give it away) Looks to me like it's from '73-'77 a-body style, which has wider mounting ears. It also means it'll be a lot of work to make it fit in a g-body. I found that one out the hard way :/