Hello all. I would like to do a 7 1/4 to 8 1/4 swap as well. Were is a good place to look for an 8 1/4 rear end for my 66' Dart ? I have found none here in Az.
Best places to look are craigslist, ebay, contact a local salvage yard that specializes in old mopars. I have used Texas Acres to locate parts in the past if you don't mind paying freight. I have also scored parts through making connections at swap meats, auto auctions, flea markets, where sometimes you get a call weeks or months later from somebody who has located your part.
FYI, if memory serves the only factory correct width 8-1/4 comes from an A-body so it is important to know the origin of the rear axle if not in the donor car and even then you should measure to be sure.
Also, you will have to switch to large bolt pattern wheels on that 66' Dart if you swap in an 8-1/4 with stock axles/drums. Then you will be swapping front drums to disks with the larger pattern up front:)
