[Schurkey]

Interesting. Thanks for that.

Re: voltage at the pickup coil connections

GM uses a bias-voltage supplied to the pickup coil as part of the dwell-variation and/or current-limiting circuitry. This bias voltage is variable,

I had NO idea about this until I read through about a dozen pages of postings on a motorcycle forum--the overall intent was to replace two (4-cylinder) or three (six cylinder) expensive OEM electronic ignition amplifiers with two or three readily-available HEI modules and "distributorless" dual-spark-terminal ignition coils; and there were some problems especially at cranking RPM. It's been years--I think one "solution" was to add a resistor and external power supply to the pickup coil circuit and provide additional bias voltage during cranking. I'd have to dig up that thread and review to be certain.