This electronic voltage regulator was used on mid 60s-early 70s GM vehicles with Transistor Ignition. Since I have one of the neat old Transistor distributors, I figured I should install the regulator in my 55 Chevy too.
This is the regulator housing before cleaning.
the circuitry inside.
The rest of the circuitry. Transistor date code seems to be 1964 October 01
The schematic from the 1966 shop manual.