With a 17x8 Wheel you can fit 255 tires on there so long as your sidewall is correct.
I have 17x8's all around on my Barracuda (A-Body) and its pleanty big for what I'm running, though I always want more rubber. That's still a 9.5" treadwidth on bfgoodrich KDW sport's.
I believe my fronts are 235-35-17 and rears are 255-40-17.
However, if you get 18x10's or 18x9's you can get 275+ rubber on there.
Whatever you do, Do NOT put more backspacing in the rear. (Pushing the spokes out towards the outside) It looks kinda funny sitting there with rear tires pushed in further then the fronts.
I have 4 7/8" Backspacing in the rear, and 4" in the front. Fronts have a deepdish look to them.
If I did it again, I'd reverse that so the wheels/tires are wider in the rear.
People always give me crap about it, I'm just warning you!
Just my