1970 Dart Side Marker Light Socket help

What end are you looking for? The bulb end? I found some hard to find bulb end sockets from Napa.. they had a large book. I wasn't able to match them up correctly but they had one with fingers that would fit almost any size.

You could also search here

http://www.oemsurplus911.com/automotive/lightsockets_chrysler.htm

And do some google searches as many other places sell light sockets.