MSD 2931 Atomic Oxygen Sensor Bung and Plug Atomic EFI Oxygen SensorEmissions Code 1: This part is legal for use on Emissions Controlled Vehicles when used in accordance with the manufacturers application guide because it has a California Air Resources Board Executive Order number or is a direct or consolidated replacement part. The following vehicles are considered Emissions Controlled... 1966 and newer U.S. manufactured California Certified... 1968 and newer U.S. manufactured Federally Certified... 1968 and newer Foreign manufactured...