8" Rallye Wheels for 72 Duster?

I'm wondering if anyone out there has put on 8" wide Rallye wheels on the back of their Duster. I have a 72 with an 8 1/4 rearend, and stock suspension. I would like to put 255's on the 8" x14" rallyes sold by Wheel Vintiques. Back spacing is 4.5" Any help would be appreciated.