We are considering a conversion. Leaning towards a 28' box with a 106" BBC truck to keep overall length managable. Want to be able to tow about 15K lbs as well. Ideally, what HP/Torque ratings would suit this setup. I have looked into Freightliner, International, and Kenworth so far. They seem to run about 300 - 330 hp and 950 to 1200 ft/ld of torque. It is all so confusing looking all these numbers. Any suggestions appreciated!