427 must never have been in the mountains with a small class A (or anything else for that matter) and a large trailer---its a hand full when the brakes get hot on the trailer and the tow vehicles brakes aren't adequate to slow both. Ever rode up an escape ramp? I would want (and have) an exhaust brake and enough tow vehicle stopping power to get it stopped----up hill don't matter because lack of power generally won't get you killed but not enough brakes could. Can't tell you how many wrecks I have seen between NC and Charleston, WV on I-77 just because of not enough tow vehicle.....