This is my set up. 96 F-250, 4.10 gears 5 speed, ATS turbo, and a chip, 9 foot camper, and a 22 foot BBF powered Thunderjet. This combo weighs in at 19,600lbs I pull the 4-5% grades at 65-67mph, I am not easy on the go button but I get around 11 and have seen 12 with this set up.