ib516 wrote:
The one pickuptrucks.com tested was a 2015 xlt crew cab 4x4. They calculated the payload to be 2880#. That was a 6.5' box. A longbox would be less as the truck is at the class max of 10k# GVWR.
All other things being equal, a longbed will have a lower tow rating than a shortbed truck.
Link
The 10k GVWR on the F 350 actually reduces the legal payload. :h to avoid certain license/taxes in some states I suppose. Without it the truck you describe should have 3800 lb cargo, and 12500 tow rating these are of course just approximate guesses depending on configuration, options, trim level etc.