123 distributor and ballast resistor

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ES 1800

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I am going to install a tune-able 123 distributor in my Zenith-carbed '73CS. Do I need to remove the ballast resistor form the circuit?
 
The straight up answer to your question depends on which coil you have. The original black coil was intended to be used with a 1.2 ohm ballast resistor and I believe you should retain the ballast resistor with this coil and modify your wiring for the 123 accordingly.

I hesitate a little bit because I would recommend that you replace your coil. I replaced my coil when I installed my 123 with a Bosch blue coil, which does not require a ballast resistor because it is internally regulated. Note too that you should consider replacing your plug wires so as to ensure you have consistent resistance on all six. And replace your plugs.
 
Good information. Thank you. I think I have a Bosch Blue coil setting around.

What is your recommended source for plug wires? Summit? Jegs?
 
Got my wires from bavauto.com Works fine. Note that the factory round tube wire holder isn't used and it's a flat piece now.
 
Kingsbourne has the nicest plug wires imho, and the insulators can be removed for threading back in the tube per HBChris.
 
Last edited:
On the same topic, I purchased the 123 - my car has the old Jacobs blue coil and ignition. I'm assuming I should remove and go with Bosch and new wires as well? Converting to triple Weber's and cam so the 123 was a no brainer


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I have a bosch red coil and 1.8 ohm resistor with the 123. Works great and fires up instantly with the webers. Its a good idea to start with fresh ignition components.
 
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