Altitude Compensator: Description and Operation

This dual vacuum switch assembly (S1 normally CLOSED, and S2 normally CLOSED) is used in the 5.0L 4-V HO with manual transmission and the 5.8L 4-V to provide an air bleed to the carburetor for the high altitude calibration. S1 will open above 5.0 ±0.5 inches of vacuum, while S2 will open above 10.0 ±0.5 inches of vacuum.