1980 300sd

I have a raspy open header kind of noise that I can not isolate.

I bought the car, it had not run in three years, it was parked because it started smoking. I was ale to get it started, it blew a lot of soot and black smoke and had a nasty noise.

I have cracked each of the injectors to bleed off any air. I adjusted the valves, all were a little tight. I checked the turbo by keeping it from turning with the engine running, noise did not go away. When I had they valve cover off, the chain seemed to have a lot of slack, but I do not know what is normal.

The car starts right up every time, it just has a terrible noise.

Any ideas where to go from here?