I put some taller wider tires under my 82 Trans Am and one side started biting into the sidewall just a little bit at the top 1/2 to 1" of the tire. I used a plumbob and found out that my rear end is offset one half inch to the side that's having the problem. Is there a way to correct where the body sits over the rearend?

 

An adjustable panhard bar. it will allow you to recenter the rear and should take care of the rubbing problem.

 

I discovered the same thing when I went to fit my 315s on. I used 1 long string with a washer on each end as my plumb bob, so that I could check both sides together while I adjusted mine.

 

The rearends a Moser 12 bolt with a 4:11 gear and the wider tires are some Hoosier Quick Time Pro 28 x 11.5's. I was running the 27 x 10.5's but a new motor and crappy track prep by the dragstrip owners made me go back to the bigger tires. I'm looking at a Hotchkis adjustable panhard rod at Summit for $108 but Christmas has me by the short hair financially at the moment. Oh yeah, and my plumbob was a piece of nylon twine with a hex head nut tied on the end. Crude but effective.