I'll share our experience... our 32' "C" rides on a 4500 Chevy chassis and weighs about 11,500 ready to go. We towed a 3700lb car from Raleigh to Spokane and back with layovers in Nashville, Estes Park, Spokane, Salt Lake City, Durango and to Estes Park a second time. We pulled mountains it seems like every day...LOL. Met many folks along the way with large Ford powered "A's" and "C's" pulling toads over the same mountains. No one we spoke with ever seriously complained of lack of power. Oh yeah, several passed us along the way! Those V10's are very impressive!
Don't let that V10 scare you away from what you want. I will however, second those comments by Ron regarding weight and loading.
Good Luck,
Gary