The fastest one for me was a Dodge dually built for pulling I had for a short time. I didn't really want it, but I got a big salting job in the late fall one year and needed a 4wd dually to put a new spreader in. It was one of my friends and I knew it would work. I don't know what all was done to the motor, but it was unbelievably fast. Especially from 50mph and up, it would pull reallllly hard. It had air lockers and the whole deal. I sold it because it didn't really fit in with the rest of my stuff. I was thinking about this because last week I found and bought an 8.1 gasser in a regular cab 4wd GMC. Probably the fastest gasser 4wd I've been in. Almost 500 cubes and not a lot of weight. It wants to move. I know weird topic, but how about you guys...