The tell is the starter. Starting in the early eighties, MBs inline engines developed a "lean" to the right. Engines with the lean are compatible with others of the same family, i.e.: the M102, M103, and M104. V engines have a different bolt pattern from either inline configuration.


In theory, if you could find a transmission from a late W123 with a M102 2.3 four cylinder engine, you'd be able to use the 300D engine. I say in theory because there are lots of unresolved questions like engine mounts, radiator compatibility, cross members, driveshaft, etc.


Jim

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14 E250 BlueTEC black. 45k miles
95 E320 Cabriolet Emerald green 66k miles
94 E320 Cabriolet Emerald green 152k miles
85 300TD 4 spd man, euro bumpers and lights, 15" Pentas dark blue 274k miles