Chevrolet Full-size Cars 1968-1978 Repair Guide

Vacuum Diagrams

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Following are vacuum diagrams for most of the engine and emissions package combinations covered by this guide. 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's 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.



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Fig. Fig. 1 Vacuum hose diagram-1971 V8



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Fig. Fig. 2 Vapor control hoses for 1971 L6 engines



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Fig. Fig. 3 Vapor control hoses for 1971 V8 engines



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Fig. Fig. 4 Vapor control hoses for 1972 V8 engines-C60 is for A/C equipped engines, LS3 is the 402 cu. in. engine, LS5 is the 454 cu. in. engine



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Fig. Fig. 5 Vapor control hoses for 1973 L6 engines



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Fig. Fig. 6 Vacuum schematic of the EFE system on 1976 L6 engines



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Fig. Fig. 7 Vacuum hose diagram for 1976 V8 engines-305, 350 cu. in. with 2-bbl. carburetor



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Fig. Fig. 8 Vacuum hose diagram for 1976 V8 engines-350 cu. in. with 4-bbl. carburetor, EFE and AIR



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Fig. Fig. 9 Vacuum hose diagram for 1976 V8 engines-350, 400 cu. in. with 4-bbl. carburetor



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Fig. Fig. 10 Vacuum hose diagram for 1976 V8 engines-400 cu. in. with EFE and AIR



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Fig. Fig. 11 Vacuum hose diagram for 1976 V8 engines-454 cu. in. with EFE and AIR



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Fig. Fig. 12 Vacuum hose diagram for 1977 L6 engines-250 cu. in. (Federal and high altitude)



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Fig. Fig. 13 Vacuum hose diagram for 1977 L6 engines-250 cu. in. (California)



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Fig. Fig. 14 Vacuum hose diagram for 1977 V8 engines-305 cu. in. with 2-bbl. carburetor (Federal)



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Fig. Fig. 15 Vacuum hose diagram for 1977 V8 engines-305 cu. in. with 2-bbl. carburetor (high altitude)



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Fig. Fig. 16 Vacuum hose diagram for 1977 V8 engines-305 cu. in. with 2-bbl. carburetor (California)



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Fig. Fig. 17 Vacuum hose diagram for 1977 V8 engines-350 cu. in. with 4-bbl. carburetor (Federal)



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Fig. Fig. 18 Vacuum hose diagram for 1977 V8 engines-350 cu. in. with 4-bbl. carburetor (high altitude)



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Fig. Fig. 19 Vacuum hose diagram for 1978 L6 engines-250 cu. in. (Federal and high altitude)



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Fig. Fig. 20 Vacuum hose diagram for 1978 L6 engines-250 cu. in. (California)



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Fig. Fig. 21 Vacuum hose diagram for 1978 V8 engines-305 cu. in. (Federal)



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Fig. Fig. 22 Vacuum hose diagram for 1978 V8 engines-305 cu. in. (high altitude)



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Fig. Fig. 23 Vacuum hose diagram for 1978 V8 engines-305 cu. in. (California)



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Fig. Fig. 24 Vacuum hose diagram for 1978 V8 engines-350 cu. in. (Federal and high altitude)



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Fig. Fig. 25 Vacuum hose diagram for 1978 V8 engines-350 cu. in. (California)

 
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