I have a 98 3/4 ton with a vortec 454 in it. I have done some mods but a cam and computer tune are next. so far i have msd 6al box, blast 2 coil, taylor 8mm plug wires, tb spacer, k&n filter, baks powerpack exhaust system. runs like a top. i normally haul our race cars down the highway about 85 or so and get 14 mpg pulling 13000 lbs.