Dana 60 in my 73 duster?

As of now, I am running Mopar rallies 14 inch, which has a indy profile, Mickey Thompson n 50 on the rear now. But I am not having any luck finding a replacement tire for that size. So I may have to go up to 15 inch rallies. , I just didn't know if cutting the rear end down to a specific length would help me out in the long run. Or make it a stock replacement width Dana 60.

I regret going stock width on my Dana in my 68 barracuda. Also regret not relocating the spring perches. Yeah it can be fixed, just a pain.