I tried to find the special CAT instructions that talked about this. No luck, but I bet the parts guys have it somewhere.

I do remember that at one time, CAT factory allowed an incentive program(thru parts) to allow customers to trade in a 3176 engine for a C12 Reman engine and the "core charge" was better. I believe it came with some instructions and necessary changes. Like wiring, mostly, I believe they offered an "adapter harness" back then, too.(may no longer be available) 

Other items to look at; are the position of the turbo verses your truck(exhaust manfold flange "tilt" differs on diff. trucks), and the rear engine bellhousing where the OEM mounts bolt to(are the flanges straight=flat up and down OR are they slightly angled = narrower at the top verses the bottom)

I can't remember our shop doing any of these, so I am not totally familiar with everything about this swap.