Have you tried posting your request on the DD board? Someone there knows where to find the data you're looking for.
Their address is: http://autos.groups.yahoo.com/group/DetroitDiesel/
They have quite a lot of knowledgeable DD 2 stroke guys....may want to avoid reference to a "bus."
The group requires membership, but if you own a DD 2 cycle, it may be a good idea to join. You can "unjoin," or read email on the web site, once you find what you're looking for.
A guy has been asking all sorts of abstract questions related to a bus powerplant, and they seem to be a little sketchy about such things. Great site for "real" DD 2 stroke questions.