This product is an NOS Part.
NOS items are OEM parts from Ford that have been sitting on shelves or in warehouses for years. These are often great examples of the orignal parts, but they may have scratches or other shelf wear.
However be aware that some NOS parts are "service replacement" parts. "Service replacement" parts are not exact replacements of the parts that were installed at the factory, but are what Ford considered as "good enough" and were used at Ford dealerships after the original supply of parts was exhausted.
We often leave NOS product listings on our website after they sell for reference purposes.
New Old Stock Original distributor vacuum advance control valve, also called a ported vacuum switch (PVS) valve, that was installed on select Ford models.
This is a NOS original electrical and vacuum operated switch. It has the FORD oval logo and part number D1AE-AA casting. This casting number is correct for select 1971 and 1972 Fords and Mercury. It was used on 302 351C and 351W engines. Because of the heavy demand placed on the cooling system by the factory air option this was mounted on the water outlet fitting. It's job was to switch the vacuum source for the distributor from the carburetor to the intake manifold when the water temperature went above normal. This would cause more advance, a faster idle and more water circulation. These are often broken or scarred by improper removal attempts. This is a rare original hard-to-find part and is a must-have item if you place your classic in Concours judged shows. Marked D1AE-AA, original Ford part number D1AZ-12A091-A.