Following are vacuum diagrams for most of the engine and emissions package combinations covered by this information. Because vacuum circuits will vary based on various engine and vehicle options, always refer first to the vehicle emission control information label, if present. Should the label be missing, or should vehicle be equipped with a different engine from the vehicle original equipment, refer to the diagrams below for the same or similar configuration.
If you wish to obtain a replacement emissions label, most manufacturers make the labels available for purchase. The labels can usually be ordered from a local dealer.
See Figures 1 through 31
Fig. Fig. 1: 1966-67 Positive Crankcase Ventilation (PCV) system vacuum hose routing
Fig. Fig. 2: 1968 Positive Crankcase Ventilation (PCV) system vacuum hose routing
Fig. Fig. 3: 1969 Positive Crankcase Ventilation (PCV) system vacuum hose routing
Fig. Fig. 4: 1970 Positive Crankcase Ventilation (PCV) system vacuum hose routing
Fig. Fig. 5: 1970 Vapor control system vacuum hose routing-base system shown
Fig. Fig. 6: 1970 Vapor control system vacuum hose routing-staged purge system
Fig. Fig. 7: 1970 Vapor control system and related vacuum hose routing
Fig. Fig. 8: 1971-73 PCV system vacuum hose routing. Note that Corvette uses a PCV system with a different type of fresh air hose connection. There is no PCV filter, only a flame arrester
Fig. Fig. 9: 1971 Corvette vacuum hose routing
Fig. Fig. 10: 1971 Corvette vapor control hose routing
Fig. Fig. 11: 1972 vapor control vacuum hose routing-350 engine shown
Fig. Fig. 12: 1972 vapor control vacuum hose routing-454 engine shown
Fig. Fig. 13: 1976 350 engine vacuum hose routing-4-bbl. carbureted with EFE and air injection
Fig. Fig. 14: 1976 350 engine vacuum hose routing-4-bbl. carbureted without EFE or air injection
Fig. Fig. 15: 1976 350 engine vacuum hose routing-with fuel injection
Fig. Fig. 16: 1977 350 engine vacuum hose routing-49 state 4-bbl. carbureted
Fig. Fig. 17: 1977 350 engine vacuum hose routing-high altitude 4-bbl. carbureted
Fig. Fig. 18: 1978 350 engine vacuum hose routing-49 state
Fig. Fig. 19: 1978 350 engine vacuum hose routing-California
Fig. Fig. 20: 1979 350 (910L4) engine vacuum hose routing-Federal
Fig. Fig. 21: 1979 350 (910L4RU) vacuum hose routing-California
Fig. Fig. 22: 1979 350 (910L4RU) vacuum hose routing-California
Fig. Fig. 23: 1979 350 (910L4RU) engine vacuum hose routing-High Altitude
Fig. Fig. 24: 1980 350 (910L4RU) engine vacuum hose routing-Federal
Fig. Fig. 25: 1980 350 (910L4) engine vacuum hose routing-Federal
Fig. Fig. 26: 1980 350 (910L4RU) engine vacuum hose routing-California
Fig. Fig. 27: 1980 350 (910L4RU) engine vacuum hose routing-High altitude
Fig. Fig. 28: 1981-82 Evaporative Emission Control System (EECS) vacuum hose routing-closed canister system
Fig. Fig. 29: 1981-82 Evaporative Emission Control System (EECS) vacuum hose routing-open canister system
Fig. Fig. 30: 1981-82 Air Management system vacuum hose routing-cold engine mode
Fig. Fig. 31: 1981-82 Air Management system vacuum hose routing-warm engine mode
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