first off, is this a 2wd, or 4wd in case i missed it
secondly, its a rack and pinion steering setup on half tons. i myself have a 2011, 5.3, 6spd "mini allison", 3.42s, extended cab shortbed
a good sized cummins weighs in around 12-1300 pounds. the frame might be ok, but the whole front end will be screamin'. so you would have too look into at least finding beefy front end components to hold the extra weight. next option would be to go solid axle. i believe theres only one guy that has done a conversion on the NNBS chevys. he used a steering box off of a 82-92 trans-am, camaro, etc if i remember right. he only posted a pic or 2 and didnt have much more info about it. so if you delete the rack and pinion and go solid, your looking, say, at LEAST 5K to do it right. axle, rebuild parts, springs, shackles, the parts list will be tremendous... so after you delete all that and go solid, there goes the factory stabili-trak.
the rear-end won't hold up long either. GM messed up here and stuck drum brakes on the half tons. so then you godda swap out the rear. big diesel torque will grenade that diff like it was made of paper. so then its a rear axle swap, and another 4K estimate.
what about all the electronics? if said truck is a WT trim level, it shouldnt be too bad. however, if its an LT with OnStar, remote start, etc, its going to be a MAJOR
PITA to make everything work. fly-by-wire, cruise... ur talkin huge headaches, alot of money, and more than likely poor results. also, you might even have to yank out the cooling system. the cooling fan is electrically driven, computer controlled im sure. ^back up to the last paragraph about electronics, the ABS would be gone, and god knows the existing brake components are all electronic.
sure you could just yank out the chevy computers, gauges, wires and everything, but thats going to be more work. if the truck is in decent condition you could part all that stuff out for a premium price and get some money back tho. im sure you could find somebody out there looking for a motor and trans combo for an 11'. especially if its a 5.3 and 6spd combo. IIRC the trans could either be a 6L80E or 6L90E. id give "circle d transmission" down in texas. those guys pump these up all the time and could prolly use it for a core charge. i think these are the same transmissions put behind 6.0s, and 6.2 camaro/corvette. circle d apparently builds them to hold 600hp consistantly with no complaints. but mind you! these are gasser applications and wouldnt hold up behind big diesel torque.
so sell off the current drivetrain to help pay for the custom fab motor mounts and other parts. might get 8k if it has real low miles. oh yea, forgot. the transfer case would have to be swapped too. thats electronic
excuse the long rant, but its just not very cost affective AT ALL. you would be better off trying to find an early GMT900 truck for cheap. as in a crap-ton of miles, broken drivetrain, etc, and just using the body and frame. right now, nobody has done this because its not cheap, and by no means easy. in a 2500 or 3500? yea sure i could see it happening. much more suitable for a swap
i believe nobody posted comments because this "swap" is near impossible for the average garage tinker-guy