Pics of pro-touring Duster with 20s?

In the back do you have any "extra" room to the springs? Would a little more backspace get you clear of the quarter?

I'm getting ready to look at wheels for my '71 EL5 GT. I'd like to go with 255's all the way around, but I think 255's are going to be tight out back unless I go with a 1/2" offset kit.

I spent months measuring and searching just to get the setup just perfect to fit right in the middle of the wheel well. It's tight. I don't recall, but it was something like less than .25" to the springs and maybe a tad more toward the quarter panel (but at least I can trim that). My rear end wasn't perfectly centered (factory tolerances) so with the wheel alone, the tire barely scraped the leaf spring on one side when it rotated, that's why I added 5mm spacers. Go with the offset kit and 275's or just stick with 245's.