Thats a GREAT looking Powerwagon.
I was having daydreams the other day about finding a regular cab longbox manual transmission used Powerwagon and swapping in a P-pump 4bt Cummins with a G56 6-speed
The 4bt should be able to sit nice and far back in the chassis, basically with the bellhousing at the same position as the 6cyl. This would make the front of the motor MUCH farther back away from the core support. This should allow you to keep the factory Powerwagon winch, CS, Radiator, etc. You would have to make up some custom hoses, but it would be connect the dots. Then throw on the full meal deal Carli Suspension system ( or whatever flavor ) and some 37x12.5x17" tires with the stock wheels or something really close. I think hutchinson has a forged hummer wheel that is suppose to be REALLY close to the specs of the stock 3rd gen wheels. I think that the 4.56 factory gears would be a little too deep for the Cummins/37s combo with the manual, but swapping in some 3.73s or 4.10s isn't impossible. The p-pump 4bt Cummins can make all the power you need. I think 400hp isn't out of the question. The hardest part would be figuring out a way to get the factory gauges to work. The best solution may be to use a truck with minimal electronics and just build a new in dash gauge cluster using independent gauges. The other interesting part would be trying to figure out how to run an intercooler for the 4bt. It would most likely have to be ahead of the factory cooling package with some interesting connecting pipes.....
So what you would end up with would be a dream rig! A slightly smaller diesel engine that could get 25-30mpg perhaps. 6-speed HD manual transmission. 4.56 gears front and back with factory electric locking differentials. Minimal lift and the ability to run a 37" tire in the factory wheel wells. The factory electronic disconnect sway bar for twisty stuff. A factory built and installed 12K winch with a nice hidden mount that doesn't affect approach angle!
MMMMMMMMmmmmmm.
If anyone builds this idea before I do they have to give me a ride!