Originally Posted by CoyoteStarfish

I think the M648 was an E class (w211) engine and M642 was used in the later w164 chassis among others and used a 722.9 transmission and if I recall, has a different bellhousing entirely.

They did however use the I-5 OM612 CDI engine in the w163 from day one, but only in markets outside North America. The fact that Mercedes avoided the OM606 for thr w163, even though it was in planning and development while the OM606 was widely used, is also why I question fitment. Or it could have just been somehow emissions regulations related.

Hoby time, on the cheap, with no major physical alterations and stock fitment is my goal with no or very little fab work. Basically hoping for it being no more difficult than swapping say... a m112 for an m113.