Let's just say that there would be only be a few trucks that would outpull you once you put in a Duramax.
It also would be a cramped affair. The Allison tranny would also require the need to completly refab the bottom so that it could work. You'd lose some ground clearance unless you did a lift kit.
The bad thing - you'd be burning up half shafts left and right. The next bad thing would be tires.
