Most 1964 1/2 and 1965 Mustangs equipped with power steering utilized the Eaton-style power steering pump. The 6 cylinder models used different brackets, but still used the same Eaton power steering pump. These 6 cylinder models also used a different center link and control valve.
In the middle of the year 1966, use of the Eaton power steering pump had been phased out. The Ford-built power steering pumps then made their way to the assembly line and replaced the Eaton pumps. These Ford pumps had a large filler neck (about 1 1/2″ diameter) and were only used for about one year. Ford then changed to the Ford pump with the narrow filler neck. These narrow necked pumps were commonly used on 1967, 1968, 1969 and 1970 Mustangs and Cougars.
