The 6.2L "C" series diesel engine was produced from 1982 through 1993. The recent listing of the "Fuel Miser" 6.5 engine by GM Powertrain is the most current rendition in design configuration(though lacking some emissions control devices).

Regarding scenario #3, needing to tow occasionally means the engine needs a turbo. If only light trailers and for infrequent towing duties, 3.73 gears, "C" cups, and a DB2-4911/6.5 injectors. If towing more or more often, 4.10 gears and possibly TD cups. Based on lots of discussions with lots of owners, there appears to be about a 2-mpg difference in cups alone.

If towing more than 5-7K, and doing it often, I'd then go to an 18:1 engine and all the other stuff necessary to keep things cool and make More Power, which is now beyond the scope of this thread.

MP