So today I cleaned all the connections and soldered all the wire-ends that weren't well-soldered before. I used the gray paste that Ron recommends for air-tight connections (can't recall the name). Now with the engine running the multimeter shows 14.6 steady, regardless of rpm. No more erratic output from the charging system. Maybe that will do it. But I thought of something else.

There's a starter button on this car. And a Pertronix with the IPD kit so you don't have to cut into the armored cable. I notice that turning the key to "start" while pushing the button...the car fires up. If I let go of the key it snaps back to the "run" position and the motor is running. Can I improve the spark at cranking by this method? It seems like it, or else why does the kit include that wire that runs to the lead on the starter solenoid? Must be a "spark while cranking" circuit there...which I haven't been using, and I never needed it because the battery has always been charged up...until a couple weeks ago.

Tomorrow when the motor is cold I'll see how it goes, and if the "key to start" method works when cold. Thanks all. Positive (+) thoughts.