rear end Width

Okay so I have a 1973 Duster that had a 7 1/4 rear end that measured 51.4 inches outside flange to outside flange. I found an A body 8 3/4 housing on craigslist then found an A body 8 3/4 3.55 posi center section and A-body 8 3/4 axles. I bought them both and put them together. (this was before I had a tape to measure the housing and took the guys word, stupid me I know) anyways tonight I measured the A body housing I bought and put together. turns out it is 53 1/2 in outside flange to outside flange or 53 1/4 center to center. which from that chart says it's a B-body early 60's rear end. Im beside myself right now. I measured the axles and I get roughly 27 and 7/8 or close enough to 27 and 11/16.

Just for grins and giggles i slid in the axle (with green bearings and backing plates) with no brake backing plates and right when the axle stud plate met the top of the studs i turned the rear end and it was grabbing. It was suspended in there from about 1 in out before i hit the bolt tops but I don't think I grabbed teeth? I dont know much about this rear end stuff.

SO is it expensive to have my housing cut down and rewelded? or should I buy new axles and bearings and have to long a rear end? any insight would greatly help.