Sorry for the delay in getting back to this. I'm working out of town and only have weekends to visit my car.

I think the problem may of been resolved or at least I can drive the car for more than 1/2 hour without the ignition failing. It must of been that extra ballast resistor or a high resistance from the taped splice. The car has been working for 7-8 years and only periodically had ignition issues so I'm assuming one or more weak links in the ignition began to fail.

Here's the wiring as it stands now. Some of the colors were hard to see until I cleaned the wires off with solvent.

5 hours ago, Jeff Berk said:

I think the problem may of been resolved or at least I can drive the car for more than 1/2 hour without the ignition failing.

Here's the wiring as it stands now.

Excellent! Glad it's working. And I agree with the assessment that it was either the second ballast resistor or just a bad connection.

And the schematic sketch you posted looks good. It's the same thing as suggested earlier with the inclusion of the tach (blue) wire connection. Glad that worked out as well!

Glad to here that my suggestion hopefully was given some thought.

Sorry to have to revive this discussion but I have some additional information regarding the second ballast.

While searching for an answer to another question, I stumbled upon the source of the second ballast resistor and now wonder if I actually need to add one back in. This figure appeared in https://www.zhome.com/ZCMnL/tech/MalloryDist.htm

It shows a second resistor supplied by Mallory, I'm assuming their part No. 8214. I have an e-mail to Holley's technical support so hopefully they will get back to me.

Does anyone have a UniLite and Promaster Coil setup in their car and if so are they using two ballast resistors.

Note that my car has been running fine without the second resistor but I don't know if I'm causing a potential problem with perhaps supplying too much voltage to the ignition module or whatever.

Looks like they wanted to restrict current through the coil during operation but weren't too worried about the sensor and module under the cap. Seems odd, but it was early days for electronic ignition. The coil primary resistance isn't that low. One of the ironies of restricting current through a "high performance" coil is that it reduces performance.

You can spend the time to get it like they wanted it to be but the reality is it's old electronics. That's probably why it's overheating. Starting to fail. Either the coil or the module. Most likely the module.

https://www.jalopyjournal.com/forum/threads/what-was-the-first-year-of-the-sbc-bbc-mallory-unilite.839756/

https://www.summitracing.com/parts/maa-29440

Summit Racing Part Number: MAA-29440

UPC: 085132294404

Coil Style: Remote mount

Primary Resistance: 0.600 ohms

I called MSD tech support and if I understood them correctly, I need 2.0 ohms. With the Mallory coil being 0.6 ohms, I need 1.4 ohms of resistance. The stock ballast resistor is 1.3 ohms so I think I'm close enough if my stock resistor is still in specs.