[DavidG]

Didn't I post one (an illustration, not a photo of the four-cylinder electrical system) earlier for you?

Coil failures are not unknown, although much rarer with an original 4-cylinder coil than with a V-8 coil of the same era, and you have a coil. The original location was on the upper vertical portion of the firewall, more or less in the center, on the inside of the car. It shows in a photo that was posted along with the above referenced illustration.