I believe 2500 diesel and 454 have the full floating 14 bolt. 2500 5.7 got 8 lug SF. All 3500 got the FF, regardless of engine. I can't remember on the hydroboost if some 2500 had that or not. Again, I "think" some options had that. The biggest deal is stopping when towing, at least in my experience. Accelerating will be slow and cars can pass you (no big deal,) but when you got to stop in "x" feet, you have no option. Also, I believe the all towing options had the engine oil cooler.