The early Dakotas had a shorter engine bay, so used the Magnum V-6 engine. Chrysler designed that engine to just for the Dakota (kludged, chopped off 2 cyl from V-8, vibrated badly). About 3 yrs later, they found room to squeeze the Magnum V-8 engine in the Dakota, so dropped the V-6, using left-overs in RAM Vans for a few years more. Still, the Mercedes engine may not fit even the later ones.