Drum to Drum measurement

I need the Drum to Drum measurement on a 1972 Skylark 8.5 rearend. Mine is in storage and I am looking at a 12 bolt schevy rear end swap.
Thanks
Tim

 

I measured mine tonight, it is 53.65" inside drum to inside drum. This is the easiest way to measure it, specially when it is on the car and tires are mounted.

 

Craig, did you measure from the backing plates or the back of the drum lip?
Tim

 

Drum lip to Drum lip.

 

12 bolt

68-72 12 bolt will be the same. 65-67 are 1" shorter and should not be a problem either. Jim

 

Thanks Jim, this one was in a 1965 chev pick up. Do you forsee any bolt in problems?
Tim

 

12 bolt

I have no clue on a truck rear? I deal with car rears. What does it measure. Jim

 

The 12 bolt truck is not gonna happen, besides a number of other differences

 

'65-82 12 bolt Chevy pickup rears will not bolt up (directly) in GM A-bodys. The 12 bolt pickup rears are too wide & attach differently. While most '65-66 & '67-72 GM 1/2 ton pickup rears had a style of lower control arm mounting, these truck housings lack '65-72 A-body style upper control arm mounts. GMC versions of same 1/2 ton rear in late '60's through '72, used leafspring mounts, so even more different. Internally, GM 12 bolt truck ring & pinions are different than 12 bolt Chevy car, won't interchange.

Back to original r/e width question...
'71-72 8.5 A-body rears & '68-72 "Chevelle" 12 bolt rears measure 55 1/4" inside of backing plates to inside of backing plates. Overall width wise with drums, outside of drums to outside of drums... 61 5/16". '65 & 66 Chevelle 12 bolts will be 1" narrower. Hope this helps.
:3gears:
Roger