Depends on the brake set up. Stock stuff you can run a 9" wide front rim with maybe a 255 tire? Out back there arent many options, but maybe a 10" wide rim with the right backspacing, and a 285-295 tire. I know a friend running Nitto 315s on 17x9s on his fox, and i will have 285s on 18x10s on mine!
Best tire combo would be a 245/45/17 in the front with a 275/40/17 in the back .. they match up almost perfectly .. 9 inch rims would be perfect for both .. you could go with a 9 inch rim in the front and a 10.5 in the back but a 10.5 might not fit snug on a 275 in the back.
ok so probably just stick with a 9" rim all around. im close to picking up my first stang and still remember what my brothers car (93 gt w/bolt ons) was like with traction so i want some fat meats out back to put the power to the ground.
i'm running stock suspension, 245/45/17s up front (9" cobras) and 275/40/17 in back, and the rear rubs the fender lip under HARD cordnering, i think its close to the max....
I had 17x9's all the way around and they were a bit too wide for my liking in the front. I switched to some ROH ZS wheels, 17x8.5 up front and 17X9.5 in the rear and love the way they fill the fenders.