Need help with rear suspension

[sam's 72]

I am finally getting close to having my 383 finished for the 72. What I want to do before I drop the engine in the truck is set up the rear suspension. This is what I want to do. I am going to replace my 12 bolt with a ford 9 inch. I bought a set of weld drag lites for the truck, the back rims are 11 inches wide. I want to run Mickey Thompson sportman pro tires on the back. I want to put as wide as tire that I can get under the back with out tubbing out the truck. I do not mind cutting the rearend housing down some to help me out, but I don't want to have to cut into the back fender wells to make this set up work. Doe any body know what is the widest tire I can go with and how much I need to cut down on the rearend houseing to get the tire up under the rear fender wells with out cutting into the rear trailing arms or tubbing out the fender wells? I have seen this done before on our trucks, but don't want to buy the tires untill I have a better handle on how much modifing to the rearend needs to be done. so help me out here guys.
Sam