72 duster firewall wiring questions ???

You have a shop manual:

http://www.mymopar.com/index.php?pid=31

The 72 manual, by the way, actually came from this site, compliments of AbodyJoe

On the firewall you cannot really eliminate anything except the resistor. Basically you hook everything together that comes to the two ballast terminals, then use the original coil+ wire to feed the new system.

You MUST have all the wires connected. This is because the key switched "run" line goes dead during crank, and originally, fires up the brown that went to the coil + side of the ballast. That is the ONLY source of ignition voltage during "start."