Are you asking about using your OM617 in another car or putting a gas engine in your W123?

Consider the variety of engines that came in the W123:

- M115 (200, 230)
- M123 (250)
- M110 (280/E)
- M102 (200, 230E)
- OM615 (200D)
- OM616 (240D)
- OM617 (300D/t)

About the only commonly available gas engine is the M102 out of a 190E. There are M110s out there but bringing one back to spec is an expensive proposition and they're maintenance hogs as I understand.

As for dropping in an OM617, it should fit in just about any RWD or 4WD frame that takes a front sump engine. Except maybe a Pinto

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