Just took ownership of a '73 450sl

Hello,
I just took ownership of a 1973 450sl that needs lots of work. It runs but I'm not familiar with Mercedes, at all. I'm here to learn.
 
My first question is what class of car is this?
What kind of gas should I use?
What kind of oil and filter(maker) should I use?
 
 
Thanks for answering any questions.
 
John

Really, no one knows?
 
OK, I'll figure it out on my own then...