The reason why you can't find any info thru Cummins is because they use a cpl number for finding parts and info and the 250 Cummins (military version ) does not have a cpl number on the data tag makes it a big pain to locate parts another problem is most of the 855 Cummins family had different parts, same block different injectors,pump,pistons,etc best thing is to upgrade to a 335 Cummins same basic engine just had a turbo and piston squirters and they are easy to get parts and are everywhere
335, 350, 400 any of these are availible at truck wrecking yards, many guys on here myself included have yanked the turbo manifolds, cross over pipes, intake and aftercoolers, Jake brakes etc off the civy trucks and bolted them onto our 800 series trucks... (Jake brake warning)-if you do jakes past the rear two heads you will be cutting the hood. 25A, 25B, 30 and 425 Jakes are the compatible ones. Remember these are 12v thus wire to one battery. Nice write up on here about it on an 818.
As far as the whole engine,,, you can drop it into your chassis and bolt your military stuff to it.... Freightliners, White, GMC, Petes, Cab overs in the 70s all ran the Cummins in some configuration.
The parts girl at Cummins cant find my engine number or CPL for my military 250, recon'd in 1988. Oh well,,, I was lucky enough to find this scrap engine which is a 1977, and I just use the engine number off it. Or part numbers I scrounge from SS. you will find that the green paint and the NSN number make the price go through the roof. The 855 was the predicessor to the N14 and some of the early N14 parts look really close to being able to fit... Like the BHT3B turbo is the replacement for the VT50, found on these early 855's, Everyone knows the HT3B but they pass over the VT50, thus somethings are easy and cheap. Remember the Unckle Sam had 19 year olds full of piss and vineger driving these trucks so he put the cheapest easiest to replace engine in them that contract could get....
The NHC/Cummins 250 motor is called a Cummins 855 in the civilian market. It's a 855 cubic inch or 14.0 liter motor. It's almost as common as a Chevy big block 350. It's had lots of uses in the civilian market from trucking to farming. It's a good solid motor with a heck of a lot of torque!
Eric
HMMMM!!!!!! I worked in GM muscle car salvage for almost 10 years and I never found a "Big Block 350 Chevy".... Found plenty of Small Block Chevys and Big Block 396's, 379's 427's 454's......
(bonus,, who can tell what the 379 was........yes Im stiring the pot...(where is that smiley)