On the Chilton book, there is a chapter about "emission controls". 12 different systems were installing in our cars.
CVS: Crankcase Ventilastion System (67, 68)
TAC: Thermactor Air System (1966)
IMCO: Improved Combustion Emission Control (1968)
DC: Deceleration Valve (1969)
DMS: Distribution Modulator System (1970)
SDV: Spark Delay Valve (71 to 73)
ERC: Exaust Gas Recirculation (73)
ESC: Electronic Spark Control (72, for States and Canada)
TRS: Transmission-Regulated Spark (system I have)
TAV: Temperature Activated Vacuum (73, 6 cylinders)
DVS: Delay Vacuum By-Pass (73)
EEC: Evaporative Emission Controls (69, California)
I didn't heard about since I broke the sensor on my gearbox. It's always nice to discover new subjects on our cars.
But unfortunatly, looks like not easy to find a new parts