no spark

You can check the continuity at the steering column wiring harness connector and if good there move on out through the car. You should have a dark blue for Ignition 1 (Run) and brown for Ignition 2 (Start). These two diagrams should help.
http://www.mymopar.com/downloads/1970/70DartA.JPG
http://www.mymopar.com/downloads/1970/70DartB.JPG