NOS or new old stock, California emissions 390 engines only. Uses 4 bolts for mounting the drive pulley, the 390 pump has three air ports on the reverse side. Ford part number C6AZ-9A486-E. For 1967 Mercury Cougar with California DSO's with S code 390-4V engines. Also fits Ford Mustang and Thunderbird, with other Ford and Mercury vehicles all sold in California 1966 and 1967.