I know the one with the 5/8" bolt will work on the factory steering knuckle. My only concern with the 7/8" bolt is would it be just big enough to weaken the OE knuckle where it connects? That is what I don't know. I am inclined to think that it would work fine, but I am unsure. I would call and ask, maybe they have put this on a OE jeep knuckle and know for sure. If it won't work, I can tell you that the 5/8" will be plenty strong for some serious junk!