From your other post I gathered that the truck is a 3/4 ton. I run 32's on my 1/2 ton with a 2.5" lift on it, and I cannot make them rub. I think my ride height is pretty comparable to a 3/4 ton, maybe a tad higher. I think 33's would rub on mine though. A bit of fender trimming and you'll be golden.
I've trimmed some on a lifted truck to fit 39.5's, and it's pretty straight forward. Use a sawzall, with metal cutting blade on it, and figure out how much you need to take off. Probably just a little bit on the front and rear bottom corners of the fender. Put the tires on, turn the wheels, flex the suspension, and check for clearance. Don't forget to treat the bare metal so it doesn't rust.