I'm the guy who put the Mercedes diesel in the International. I took a motor/tranny from a 83SD and put it in a 73 International Travelall(suburban). I also added an overdrive unit. Gets about 25mpg. I also boosted up the turbo, installed an intercooler and added propane injection. Its no rocket but I easily maintain 65 on the hwy. Also this winter I had my plow on the front and boy did it push snow. Plowed for 2 days and used 1/2 tank of fuel. Weighs in at 6500lbs with the plow!
I am so impressed with the 617 motor as well as Mercedes in general, that I just bought an 83TD with a blown motor and replaced it with a salvage yard motor. A great car that shortly will be my wifes daily driver.
After working mostly on old International trucks were every bolt fights you, Its nice to work on a perfectly engineered machine where once you crack the bolt loose, you take it out with your fingers. You mechanics know what I mean.
Anyway, I firmly believe that as long as the vehicles engine compt. is big enough the 617 is an awesome motor to install.
PS. The travelall will be running on waste vegatable oil soon (svo)

Mike Moran