If you want to run square with big wheels, you can go up to 18x10 and a 285/35/18 with work on the front fenders (rolling, flaring, brace extensions) and a 1/2" spring offset in the rear. With that set up you'd be best off with a 65-67 or 68-70 B rear and your 18x10's with offsets in the +30 to +40 range with the wiggle room being what disk brakes you're running and maybe a small spacer.