I'm using the flywheel from a 1972 220d with an om617. I think this flywheel is even lighter than the 240 flywheel. It has stalled because of the light flywheel a only twice that I can remember in the 2 years I've been running it.

One other thing worth mentioning is that the crossmember and shifter rods both bolted up to the w123 with no modification.