My uncle has a 2012 Duramax, 4-door, shortbox, auto. My dad has a 1991.5 Turbo Intercooled Cummins, single cab, longbox, Getrag 5-speed. Both are bone stock (well, I turned up the fuel a little on the Cummins, but not even enough to smoke). With a 5-foot load of wood in the Duramax and an 8-load...