Yes, very good point. Also, one of the gaskets from MB had a mistake, I think it was the 7.6 gasket. We went around with that for a while, right Scott? I wonder if they fixed it. A water passage hole was in the wrong place, one of the ones right between the combustion chamber rings.
As for the Unimog, I believe that the M180 that was put in the Unimog was a lower compression version, maybe the 6.5 or 6.7 220 head. They do crop up. Manfred Prinz Westfierld 4x4 (ebay blueman636) is a good place to ask. You might find a new one.