The 1st Gen Cummins trucks are some of the favorite machines I've ever owned/operated. I've got a lot of time behind the wheel of them, both auto's and manuals, and I have some good tech I can link for you.

Bottom line: Classic trucks that can make an easy 300hp/650tq and an honest 20 mpg all day long. Great machines - easy to operate - easy to upgrade - in many ways a lot like maintaining an old-school hot rod.

Very inexpensive to up the power to much more useful levels - not the dyno sled-puller nonsense, but actual useful power. Every factory automatic ('diesel' 518/46RH) needs a fresh torque converter - the factory units have a lot of slop (heat) in them, which led to the undeserved bad reputation of the diesel 518, especially when the power was tuned up a little. The 5-speed (G360) trucks were nice, and could also benefit from a bit better clutch.

Engine. Easy to maintain, easy to BOMB (Better Off Modified Baby). Simple upgrades net an unbelievable improvement in power and drivability, with zero reduction in mpg's. Best upgrade = $20 "366" spring

Drawbacks. They're old, and stuff wears out, and all of it is replaceable or bypass-able or upgradeable. Suspensions (especially the 4x4s) are pretty stiff, all of which is easy to improve.

I wish I still had one.

For anyone that might be interested, here's a link to the diesel section in RCC (Ramchargercentral) with lots of additional links that may help better understand the OPs question. Some of the links I've personally developed/compiled from many sources or my own experience, including multiple Cummins swaps I and many others have done, all with pics and tech and explanations along the way.

https://www.ramchargercentral.com/forums/diesel-talk.117/ (definitely check out the 'De-computerize your Dodge' thread)

- Sam