what's wrong with the 6.5 turbo engine, it propelled up armored rigs around pretty darned good. The dirtymax might fit better being a v-8 but why would you change to drive by wire ,on a vehicle intended to drive in deep water. If you want to,burn all 4 tires what is your plans for differentials and axles. A 4 b reliably will make about the same as a 6.5 turbo diesel so why do it. A 6b would just be too long, Those are my opinions, just like backsides every one has one, and I think mine is the only one that doesn't stink. Now if you want to do it because you can, than go ahead, but anything other than a 6.5 turbo diesel, I don't feel will improve the vehicle overall