My current set up is 215/45ZR17s on the front, and 235/40ZR18s on the back. I rolled the bottom lips of my fenders and get no rub with lock to lock turning. On hindsight, I would have went to 9"s on the back with the appropriate tire since there's lots of room with the stock setup. Here's my ride: http://rides.moparmusclemagazine.com/ride/1207287/bigd123/1973/plymouth/duster/photos/1.html
Oh, and 7"s on the front, and 8"s on the back.