Dodge actually was making HUGE 1 1/2 4x4 trucks for the military since 1933. They were the first to use a in/out front drive lever and transfer case. Before that they were always locked into all wheel drive and that was a major advance. The early ones looked like some huge model A pickup or something with a military bed on the back and were very tall with lots of ground clearance.
Other makers were building all kinda of oddball trucks for them back then including early FWD trucks and Ford, plus the early just before war stuff everyone was prototyping like Chevy and GMC with early 4x4 and 6x6 trucks that also used civilian cabs with beefed up running gear and the grill guards/cages on the nose to protect them a bit.
The big thing on the Korean/Vietnam trucks was 24 volt electrical, and water proof everything with provisions for adding a snorkel system so as long as the engine could get air they could drive underwater.
They did it on some of the later WW2 stuff too but most of the early stuff wasn't water proofed from the factory.
So that is probably the main difference from the same engine in civilian use hence the special distributor, carb, and other stuff.
The basic Flathead 6 has been around since probably when Dodge first sold a 6 probably in the twenties and the displacement just kept getting bigger.
My 41 cane with a 218 but had a 56 Plymouth 230 in it which had a lot more power but externally was identical and would bolt directly in, a popular swap to keep em going back in the day.
As far as cars I've had a 69 Sport Fury with a 350 horse 440, the Duster, Dart, another /6 Dart, 72 Satellite a friend and I bought cheap to flip with a 318, a few parts cars mostly to upgrade or repair the Dart over the years and a 50 Dodge Coronet 2 door I never got running with a fluid drive trans and a flat head like the Power Wagon, plus a bunch of forgettable cars I thought I was going to drive or gave up on after wasting money trying to fix em up and drive them.
The Dart I upgraded everything to 340 specs with a 383 nose that was on it when I got it. I put a performer intake, Thermoquad carb, early 340 manifolds, 3.23 sure grip, poly front end bushings and front and rear sway bars.
I also have all the parts to convert to big bolt disk brakes in stock and later police 15" rims. It also came with fast ratio 16 to 1 manual steering which was a rare option and makes steering much quicker but harder to turn.