Alec, pull the vacuum pump to see if it's intact. With the 603.96x, unlike the 603.97x, my first suspicion would be that the vacuum pump spat out something that wound it's way down the timing chain.

If that's the case, thank goodness for the separate side chamber for the sump.

Sixto
95 S420
91 300SE
87 300SDL
83 300SD