Spend $14 at a CAT scale to find out where you stand currently. Why guess if you'll be over any of the new trucks' ratings?
The 2014 5.3L has about the same amount of power as the current 6.0L in the HD. If you have an older GMT800, then the 5.3L will have a little more power and far better gearing with the 6-spd over 4-spd. So a 2014 half ton will feel like a rocket. But you may not be pleased with how it handles the tongue weight and whatever you take in the truck bed. Find out where you stand and how much receiver and payload you need.