Rear diff question

See all this talk about cutting and shorting , Didn't rear all posts but am i missing something are you tubing the car . you can get a 245/60 14'' under the car no trouble or a 15'' on a rally wheel .You can get other wheels and go 265/ But here what i am getting at 1971 to 1976 darts / dusters /sport darts all could be gotten with the 8 1/4 rear this would be the same with as you rear now NO CUTTING and after 72 were 4.5 bolt patt. if you still wanted more tire under car WITH out cutting the housing and replacing the axles just do the spring relocate . or 71 to 72 and just find a pair of later axles from a body 4.5