Crankcase Ventilation Systems: Description

A "closed" positive crankcase ventilation system was first used on 1965-67 vehicles built for sale in California. From 1968 on, all vehicles are equipped with closed positive crankcase ventilation systems. System consists of a positive crankcase ventilation (PCV) valve, a hose connecting PCV valve to carburetor base or intake manifold, a sealed breather cap, an air filter assembly located in air cleaner (1968-74 models) or a mesh filled breather assembly located on rocker arm cover (1965-67 Calif. models) and a hose connecting air cleaner to rocker arm cover.