74 dart can’t get a spark

I also changed ballast resistor yesterday. Cause I’ve heard those go bad quite often
Check for power with your test light at the steering column connector (key off)
If none take a look at your amp meter connections.
Those sometimes melt and disconnect your main dash and ignition feed.

FYI, with the factory ignition box and coil you can disconnect the plug for the distributor, and on the harness side touch the exposed metal contact to ground and you will get one spark per ground touch.
(That way you don’t have to keep cranking it for testing)