The M103 and M104 have both the inlet and outlet to the radiator on the driver's side. The M119 and diesels have the outlet on the passenger side. It would be a difficult swap.
Inline 6 radiator.
http://cdn2.autopartsnetwork.com/images/catalog/wp/full/W01331901891NSS.JPG
V8 and diesel.
http://cdn0.autopartsnetwork.com/images/catalog/brand/apdi/640/8012069.jpg
I think the V8 and diesel radiator is a much better design.