I had an 03 Hemi Quad Cab 1500 and have since moved to an 08 1500 MegaCab (really a 2500) with a Hemi and 3:73 gears. The newer transmission in the 08 is what makes the difference. The gear spacing is the problem. I pull about an 8-8500lbs fifth, and I just got home from travelling up I81 north from Harrisburg to the CDN border and I could hold 50mph at 3000 rpm, the odd time it needed to jump up to 4200- 4500 rpm (on some of the steeper grades) where as someone has said, this is where the Hemi makes its power, and it does. Stick to the stock tire size. Putting on larger tires to look good just negates all your towing power
