Gentlemen, thank you for your responses. I do not wish to spend any money unnecessarily. Background - I bought the car from a second owner who inherited the car and drove it with as little maintenance as possible until it would barely run and couldn't afford a tune up and exhaust. It was let sit with filthy oil for a year or so, not running, until I bought it. I believe it did not get regular oil changes or maintenance. Reasons I think I need the chain: Loud clattering at start up. Could the tensioner be bad?
The cam: clear tapping noise from right valve cover (from the front of the car). I asked a shop owner about replacing or shimming a Hydraulic Valve Compensator (to eliminate the tapping) and he said they almost never go and it is probably the cam. Then he showed me one in his trash with one bad lobe. He did say that I could go a long time even with the bad cam, but change the chain before it jumps. He has not seen the car yet, made no firm judgement and wants to open it up before he gets all the parts. (BTW, I have no problem with anyone.) I do some work, but this is over my head. I'm sort of afraid to work on the Benz.