If it’s a 82 and nobody has swapped engines (it is a thirty year old vehicle) it came as a normally aspirated 6.2. GM never turbocharged the 6.2 and voided your warranty if you did so yourself. Back then the warranties weren’t very long so by time you figured out this is an underpowered pig, your warranty had expired anyway.
The Banks conversion was far and away the most popular turbo conversion. As somebody pointed out the Banks turbo was too small. That was for a reason. By using a too-small turbo ol’ Gale avoided the expense and complication of a wastegate. Also by limiting air the thing wouldn’t become so powerful as to destroy itself. The Banks conversion was superbly engineered for that engine.
6.2s and later 6.5s were indeed used on HMMVs and CUCV military pickups.
Some say the 6.2 was the better MPG vehicle as it had smaller pre-combustion chambers that needed less fuel to work. BTW, my 6.2 was never cold natured at all. It woke up nicely on 25 below morning out on the Great Plains. I did use the later model glow plugs.
Do yourself a favor and convert it to a NV4500 manual or resign yourself to a new automatic every 40,000 miles. Wimpy as it was, the 6.2 made nearly peak torque at very low RPM and the automatic at low engine RPM will not cool itself even with an oil cooler the size of a VW Golf radiator. The manual is bulletproof and is amenable to gearing changes and GV overdrives for max MPG.
There are stories out of Detroit how GM had an engineering “Mule” Suburban with a 6.2 and 2.73 gears (never offered commercially). Sluggish as hell but allegedly got 30 MPG real world. Salt that to taste.
Here’s your gold mine of information of 6.2s and 6.5s although the site has morphed into a Duramax site sinc e the Duramax (an Isuzu design built in a Dayton suburb under license) supplanted the 6.5.
The Diesel Page - for the 6.2L, 6.5L, and Duramax 6600 (6.6L) GM Chevrolet and GMC diesel engines.