A good source of information is to check out the available factory manuals available from cummins. (not very expensive if i may add) One of my injector and pump books provides a list of engine cpls with the application and certifications by epa/carb.
On another note who is saying a 3/4 or 1 ton vehicle is a light duty vehicle. By the time you take a 1,000 lb engine, upgrade to a 200 lb transmission/200 lb transfer case and 300-500 lbs axles and 100lb spring paks, we are talking, 6-7,000lbs as an example for my 56 s120 3/4 ton INT travel-all.
we are not talking cj-5's, are we????
ray