See if this makes sense:

- The W115, W116, W123 and W126 had the OM617

- The W114 is the 6 cylinder version of the W115 so the W114 should take an OM617

- The W100 shared the M100 with the W116 so the W100 should take an OM617 (600D 3.0!)

- The R107 shared all gas engines with the W116 and W126 so the R107 should take an OM617

- The W108/9 shared the M116/7 with the W116 so the W108/9 should take an OM617

- The W111/2 shared the M129 and M180 with the W108/9 so the W111/2 should take an OM617

- The W113 shared the M129 with the W111/2 so the W113 should take an OM617

- The W105, W110, W180 and W187 shared the M180 with the W111 so the W105, W110, W180 and W187 should take an OM617

- The W186 and W189 shared the M189 with the W112 so the W189 should take an OM617

- The W198 shared the M198 with the W189 so the W198 should take an OM617 IF you can tilt an OM67 45-degrees to the US driver side and fit a dry sump system (Diesel gullwing!)

- The W128 shared the M127 with the W111 so the W128 should take an OM617

- What's left are the W120, W121 and whatever the 170s are.

That should cover it from 1950 through 1985, should be easy to extend the OM617 through the OM603 and OM606 into the late 90s

If you want a challenge, drop an OM617 into a W201

Sixto
91 300SE
87 300SDL
83 300SD ... any takers at $1100?