We pull our 19-foot Bambi with a Toyota Tundra 5.7L V8 (381 hp, 401 ft lb of torque, 6-speed). The specs on your vehicle sound very similar.
Since our TV and Airstream easily climb the grade on the Eisenhower Tunnel (both ways), I would guess that your Ford would be fine, too.
We have towed our Bambi all over the mountain west, and we have never had any difficulties on grades. It can pull at any legal speed limit on any grade, and accelerate to pass while climbing.
However, I have never driven or towed with the Ford you describe; so this is just a guess...