For everything you ever wanted to know about the MARZ (and quite a lot of stuff that you probably didn't!), check out the article at:

http://www.modelenginenews.org/ad/marz.html

The MEN website is a great source of information on a lot of classic diesels as well as restoration tips, etc. Use the "Finder" menu under "Engines" to access these articles.

I've had quite a few of these engines in my time and still use one regularly. The most impotrtant issue to be aware of is that the shafts tend to be brittle and sometimes break in service.  You have to normalize them through appropriate heat treatment to deal with this.  It's all in the article.

Good luck with your MARZ!  A good one is a really nice engine.