I'm just gonna add that my truck got a respectable 16mpg towing my 9000lb toy hauler though the valleys all 2 lane highway 60mph very hilly and curvy. 84 F250 studded rebuilt 7.3, injectors from Russ, Rajay turbo system, 7* btdc timing, 4.10 gears, ZF5, fuel screw almost maxed on na pump. I...