Widest Tire/Wheel combo for a '72 Duster?

Check out 70duster440's site for a good look at 16's with 255's on the rear.
http://www.70duster440.com/index.html

I also have 16's, Cragar S/S 7" front with 3 7/8 backspace and 8" rear with 4 3/4 backspace but don't like the offset on the rear, not out far enough.
70duster440's fit better I think

I think a 4" backspace on the rear would be good, cause 3 1/2 gets too close to the quarter panel in my opinion.

I also had the 16x8 on the front with no interference and 17x9 4 1/2 backspace rear with 255's and they rubbed the quarterpanel slightly.

there are some pics with the 17" rears on this thread-- http://www.forabodiesonly.com/mopar/showthread.php?t=40593