8-1/4" rear end questions?

I think based on its size, the weak link in a 8 1/4 is its axles they are smaller then any other rear end in its class. I will also use the 8 1/4 in my 71 Dart. Mine is a two door. I will be adding disc brakes soon. I can rebuild a 8 1/4 cheaper then you can rebuild a 8 3/4. They stopped using the 8 3/4 a long time ago. I think the 8 1/4 is still being used. Look under a Jeep Grand Cherokee the next time your driving down the road. I did notice that the 06 G.C. are using yet another rear, but I have yet to find out what it is.

Are you limited to the tire size you can put on your car? Just wondering