hndrsonj, It pulled just fine, my F350 is set up to tow a 17,000 lb 5th wheel. It's a very treacherous road coming down out of Payson, my biggest concern was stopping. Down the long down hills, the Banks exhaust brake worked perfect, very little brake time. I kept it to about 45 mph most of the way. I did run at about 55 on the flats in the desert.
My F350's been Dyno'd at about 425 hp with well over 700 lbs of torque (at the rear wheels). It has a custom built ATS transmision and torque converter. I can pull 17,000 lbs up a 7% grade without dropping to 2nd gear. That was my goal when building this powertrain. I've done alot to keep my EGT's down as well. The Navistar 7.3 is a great engine! I have one in my Excursion as well.
In the end though, the braking is the weak point with the set up you see above. I kept my distance from EVERYONE. I did have safety chains connected before I left.