Anyone run a Ram 3500 with 6.4 Hemi?

Looking into a 13,500 lb gvw fifth wheel. It weighs too much for my F250. Does anyone pull anything that heavy with a 6.4? If so, how do you like it? Does it handle the mountains?

There was a recent test done up the gauntlet on the Eisenhower tunnel towing around 12,000 pounds with the 6.4. If I recall it got 2.8 mpg and a max of 35 mph or so. Go with the Cummins if you want to tow 13,500 pounds up a hill. Truck camper magazine also purchased a 6.4 3500 dually for carrying their cabover camper. They also commented on the fuel mileage. Get the Cummins for better fuel mileage. Get the Cummins for better resale.