First thank you, thank you Rip, for the NOS points and condenser in exchange for future cold beverages. That was the problem with the ignition.
Update on my latest diagnoses. The shaft of the '67 dual diaphragm booster need to be pushed in to be bolted to the brake pedal of my '66.
I added flat washers ( in my case, 2 on each stud = 1/4") between the firewall and the booster. Now the brake pedal can be attached with no resistance.
Test drive time. Everything feels right now, slight depression before brakes engage. Now this is the big one, when I take my foot of the the pedal, I can feel the brakes immediately disengage and the car's inertia moving the car forward again. Never once, did I have that sensation, since the conversion.
The big test, nearly an hour of 40+ miles of country back roads, with a lot of starting and stopping. She drove perfectly start to finish. Happy 4th of July to me!!