Sounds like me. I'm having some trouble finding parts myself for my 1974 280. Here are some sites that I look it. Have you emailed Phili from fastline?
http://www.thebenzbin.com/
http://www.peachparts.com/Merchant2/merchant.mv?Screen=SRCH&Store_Code=msps1
This link above is a link to search partsShop via words.
http://www.budsbenz.com/home.asp