I agree that trying to do a CAT or even a cummins swap is over most people's heads. BB62 is definantly right when he says it's over your head. Heck, l'd have a hard time doing it and I am a diesel mechanic. You are still too young and inexperienced to try something like that, and if you can't afford a late model diesel truck out of your pocket you will be out of cash with the project before you even pick up a wrench or phone. I mean that in general, not directed at you only. Trying to figure out how to make parts work and fit with each other that weren't meant to along with trying to make parts handle more than they were designed for can be a real headache. Not only that but trying to find parts to make the swap a succes could be just as difficult. Just making an Allison or clark work with a transfer case isn't easy.
Everything you do opens another can of worms, example......
You want a cat engine, you have to aquire a transmission that will work. Most that will are not made for a mated transfer case. Then you have to find a t-case designed to be in a divorced setup. You find a military 2 spd case or something, all new shifting linkage would probably have to be fabbed up......get it? Not only is it obviously a long drawn out ordeal but a costly one at that.
As far as the engine physically working...a C7 would fit in just fine. It is about the same size as a 5.9 cummins and weighs 1,200lbs, the cummins 5.9 weighs in at 1,000lbs. In theory a D60 should be able to handle that 1,200 ok but that pretty much rules out some big heavy bumper and winch.
I would love to have a marine C7 with some crazy power mods in an '03-'05 Chevy crew cab LB, Cadi Esc. front clip, Allison tranny with some sort of tcase setup, and instead of a standard D60 I think I would hunt for a new HD D60 out of an '05 Ford SD. That 60 has 35 spline shafts, bigger brakes, already setup for coils, thicker tubes, and most importantly a weight rating of 6K, enough to reliably hold up the 1200lbs from a C7 and Alli. But that would probably cost more than what I paid for my '01 Dodge Cummins just to get the marine C7/Alli/ Ford D60, and tcase setup right and all installed.
Guess since he did it so many times he was getting lazy about it. You will need custom motor mounts. I believe on that V-8 the driver's exhaust manifold was original from the motor with a fabbed pass side due to clearence issues. Also like I have stated before, he used the stock 465 4-speed in chevys. What he did was adapt a bellhousing that mounted to the engine with no mods and modified the back end to bolt up to the tranny. And I am sure when I am able to start on CAT conversions you will be the first to know of any new info. I will most definately share all info and pics I have to help you, or anyone else out for that matter. That's what it is all really about sharing info and helping people learn. 
