* The Air Injector Reactor (AIR) system pumped air into the exhaust manifold(s) to help complete the combustion process. The AIR system consisted of the air injection pump (aka smog pump), a fuel mixture control valve (1967) or an air diverter valve (1968-9), check valves, air manifold assembly, and air injection tubes (one per cylinder).
* The Controlled Combustion System (CCS) was introduced in 1968 and was used on cars that did not receive the AIR system. CCS improved combustion efficiency via recalibrated carburetor and distributor settings and higher operating temperatures (compared to 1967). The higher operating temperatures were accomplished by using a 195°F coolant thermostat (instead of 180°F) and the use of a thermostatically controlled air cleaner (ThermAC). The ThermAC system was designed to warm intake air to 100°F when underhood temperatures were less than 100°F. It consisted of a damper door mounted on the snorkel of the air cleaner which directed warm air from a heat stove on the exhaust manifold into the air cleaner.
* The Positive Crankcase Ventilation (PCV) system utilized manifold vacuum to draw crankcase vapors into the engine to be burned. Filtered air was drawn through the engine, through the PCV valve, and into the intake manifold.
In 1969, Canadian cars used the same emission controls as U.S. cars.
PCV became standard on all Chevrolets in 1968 and is still used today on all cars.