I have a '99 F250 CC SB 4WD V10-2v w/4.30's. it has over 120k on it. It did not like long or steep grades without a running start, 5er is an older Prowler <9k#. Truck was fitted out with Banks Ram Air, headers, Trans command and big dog exhaust by the previous owner for hauling horses.
If it hit a long grade or a steep one w/no speed on, about all I could get out of it was 45mph with OD off. Mpg's were 9-10 variable elevation driving. I did get 12 on the flats sometimes.
She just turned 15 and I upgraded to a Ram/Cummins 3500 DRW. I am waiting on parts for the trailer and hitch, so I haven't towed yet.