question regarding challenger electronic ignition components

[505challenger]

i have been having what i believe to be an ignition porblem with my challenger (73 340).  i have replaced alot of parts but i want to make sure i have checked all of them.  on the firewall there are 3 parts, the ignition module, resistor, and a third that i dont know what it is or what it does, can someone help me identify all the ignition related parts.  so far ive changed the resistor, module, coil, pickup coil, and spark plugs

[brads70]

The third one on the firewall is a voltage regulator. Make sure it's grounded very well to the firewall.

What is your car doing? What are the symptoms?