Not the size motor your asking about but just giving some specs out there.
We were towing with a 2012 Dodge 2500 mega cab 4x4 with the 5.7L
We pulled our 40' Cross Roads bunk house 12,000#
I added the bully dog has tuner to the truck and our last trip we took with the truck was 8hr drive and we were getting between 10-11mpg. We had also added a air raid cold air intake and a flowmaster muffler.
Had plenty of power to spare.
2016 Ram 3500 4x4 Big Horn Crew Cab, SRW. Cummins Turbo Diesel Automatic 68RFE Trans
50 gallon diesel Transfer Flow tank with the Traxx 3 system.
2017 Sierra FLIK 5th Wheel
42' Front Livingroom, 15K
Hydraulic level up system