Hello Kazoo,
We have some great suppliers which have actively supported our group by supplying information, technical help and supply parts. The Mercedes-Benz Classic Center (Tom Hanson), Buds Mercedes, K&K Manufacturing, Dan Caron, Dave Galon, Pete Lesler, Metrics, Becker Radio (Ed Ebel), Bob Geco are some of the more notable. There are more, anyone feel free to add to the list. There is an extensive listing in the Tech Manual, but those above are some of the guys that are involved and support our group. You will find these guys most knowledgeable and helpful. When you talk "W113" they understand the language. There are other parts specialists out there like "SLS" which are overseas and less involved in our group but are quite knowledgeable.
Other great resources are Mercendes-Benz Club of America. The Mercedes EPC (Electronic Parts Catalog) which is a free service to individuals from the factory. Complete parts catalogs with dealer parts numbers are available on the EPC web site for the W113 cars and almost any other Mercedes-Benz Vehicle. It is quite extensive. I don't think there is any other Auto Manufacturer which supports their vintage car enthusiasts as well as Daimler-Benz (Mercedes-Benz). The Mercedes-Benz factory still supplies some new parts for their models made over 100 years ago! Some Mercedes-Benz dealers like Mercedes-Benz of South Atlanta, have on line catalogs and pricing for web customers also. Some offer discounts and deals on shipping.