Should the ballest resistor get hot when I turn the ingition in the on position?

I bet the wiring is different between the 69 and 74 harnesses. Most likely if you compare schematics from both you could figure out what to move where. Here's some links to wiring schematics you can look through and trace your wiring by.

69 Dart schematic A: http://www.mymopar.com/downloads/1969/69DartA.jpg

69 Dart schematic B:http://www.mymopar.com/downloads/1969/69DartB.jpg

74 Dart schematic A:http://www.mymopar.com/downloads/1974/74DartA.jpg

74 Dart schematic B:http://www.mymopar.com/downloads/1974/74DartB.jpg

After reviewing the schematics it looks like there is alot of differences between them. I traced several wires on the plugs and it looks like everything is all mixed up. i.e. their not compatible. No wonder it doesn't work. It's a wonder the horn doesn't sound off when you try to start it by what I'm seeing. Sorry to say but I think your either going to have to revamp the 74 harness or find a harness off a 69 Dart V8 car.