Hot idle compensator valve assembly for many Ford engines with PCV, starting in 1964 through early 1968. Typically found on 1964-66 Ford 260-2V, and 289-2 engines with air conditioning. 1967-68 289-2V, 302-2V and some 390 engines all with air conditioning and PCV or closed emissions. The Ford assembly manual indicates that the Hot Idle Compensator Valve 'T' Assembly, was installed by removing 3/4 inches of the PCV hose, 2-1/4 inches (on center of the PCV valve). See picture for clarification. According to the Bob Mannel book on small block Ford V8 engines he states that this valve was discontinued after 11/15/1967, which is about 4 months into the 1968 model year.
Very cool detail item, for those doing concours restorations. Ford part number C4AZ-9B532-A.
*Note - This valve and 'T' assembly is used, and over 50 years old. It may or may not seal properly. It does appear that they can be sealed or adjusted.