You might be able to turn those tires at sea level, but you would not be able to get up the highway in the mountain west, let alone off-road. 33s cause significant stalling at elevation with stock gearing.(terrible with a 5spd) To wheel with 39s and a 4cyl youll need a double case for sure and new diffs and auto trans to handle the stress. Fun experiment, but for significant wheeling 39s require costly upgrades on any 4x4.