Daimler Benz began construction of a OM-312 back in 46. The 366 is a 6.0L straight 6 popper, with turbocharging and aftercooling, developing 237HP @ 2,600 rpm and 560 ft lbs. @ 1,400 rpm.
This engine has been developed since the end of WW2, just out of curiosity would you take an engine that has been put into UNIMOGS, Busses and trucks over the 6.0L or 6.4L?
Plus it is a Mercedes Benz diesel, they're cars aren't what they used to be, but given the choice, what would you choose?

P.S. these (I believe) are 1995 specs for the UNIMOG 2450L 6X6.

 

I would...

Our neighbours 78 Mercedes OTR Truck has done over 2 million miles... and still runs beautiful.

That engine you are talking about is an old-school Merc engine, which means:
1. Its actually good, and was built under the ethos "engineer to perfection"... as opposed to the crappy newer designs.
2. It wouldn't have the faintest chance of passing US emissions.

 

I don't know about number 2 on yer list BigF350. They have been running an engine around the old Uniroyal track down here that LOOKS just like an old 366 in some Ram trucks. They ain't testing for something to do. I think the design of the heads would have to change and an electronic injection system with some lean burn technology and I think this engine will pass emmissions. If not, the DC 8.1 is slated for introduction to US soil by 2008-2009 time frame. They have been toying with a Dodge 4500 series truck which is a little larger truck kinda like the F-450 but more industrial in character for the guys that need to pull the heavy trailers. I've even heard some of the guys talk about it in the 3500 series. Talk about the power war coming to a head. That should blow anything away that Ford or GM can put on the road. My personal take on the diesel segment, they already have more power than is feasible for the size and heft of the trucks. If you need that kind of power, step up to a real truck like an F550 or larger. My .02