Please, if you're talking about diesel engines, it's "Cummins", NOT Cummings. And the LMTV trucks use Caterpillar engines anyway.
I miss my old deuce, but if I'm fortunate enough to own another military truck, it'll likely be an A2 5 ton. The newer Stewart and Stevenson LMTV trucks have a fairly low (58mph) top speed, while a stock A2 5-ton will run 65mph on the governor. They also have a lot of electronics that you have to take directly to Cat or Allison for diagnostics. The do drive nice though.
You can re-gear the LMTV with gears from an MRAP if you can find them, but it's not terribly cheap anymore, and a bit of work...
None of these trucks are really suitable for overlanding, IMO. They are really big, parts are actually not that easy to find once you're outside the US, and fuel mileage is pretty horrible, particularly on the LMTV's.
Speaking of not suitable for overlanding, I see Gov Planet has lowered the price on HEMTT's... Starting for a cargo with crane M985 is only $7k. That's a LOT of truck for the buck!!
When I worked at Oshkosh Truck, I drove HEMMT's quite a bit. REALLY easy to drive, and extremely capable. And very useful with the crane! No lockers, but the rear axles have LSD's in them, and with CTIS, they'll pretty much keep up with a tank offroad. (The army's mobility mark...) And they'll run 60mph down the highway. A little faster on a good day.
![Smile :) :)](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
My favorite video:
https://www.youtube.com/watch?v=X0Vyq--p89A
Chris