8 1/4 rear end swap

Hi, I recently acquired a 71 dart with 318, front discs, small bolt pattern and 7 1/4 rear end. Ideally, I would like an 8 3/4 rear end but realize they are hard to come by and pricey. So, I'm set on getting an 8 1/4 but since they were used in so many early and late model Mopars, I don't know which one to get. I would like to find one that would require little to no installation modifications. I also need it to be large bolt pattern. Additionally, what's needed in converting to large pattern on the front? Just spindles and rotors???

Thanks