Correct PCV part number for Feb 66 K-Code?

  • OK, been chasing this one for a while and was just curious if any of you know, is the correct 66 HiPo PCV part number C5AZ-6A666-A or C5AZ-6A666-A1, or something else entirely... every time I search I come up with different answers on all forums. And if for me we can be specific as to which would be correct for my Kar, February 66 build, San Jose plant.


    Thanks as always,


    Jason

    February 10th 1966 - San Jose - Factory GT K-Code Automatic, Candy Apple Red Fastback, Black Standard Interior

  • The C5AZ 6A666 A and the C5AZ 6A666 A1 are the same part. This is the correct valve and I have a few NOS ones of these and I will get a better look at them when I return on Wednesday. I have seen the number with the A1 suffix on the Ford box but the actual part number is with the suffix A only. There is really not a Ford part number C5AZ 6A666 A1, only the C5AZ 6A666 A.


    -Fred-

    65 Koupe early San Jose Phoenician Yellow 4 speed
    66 GT Koupe Dearborn Blue 4 speed
    66 KGT San Jose fastback pony interior Silver Frost 4 speed
    64 Falcon sedan delivery 289 4 speed
    65 Ranchero 289 4 speed
    66 Corvette roadster 427/425 4 speed

  • Thanks guys...


    Fred, I've also seen this regarding the part number stamped on the valve itself stamped two ways, and I heard they were both correct for my application (see below), this is were the confusion came into play when I really started digging and found the A1 "Ford Box". But both actual valve stamps on the part I've been told are correct, but would love your opinion...


    Part# Valve Stamping:

    1) C5AZ 6A666 B

    2) C5AZ 6A666 A


    Thanks,


    Jason

    February 10th 1966 - San Jose - Factory GT K-Code Automatic, Candy Apple Red Fastback, Black Standard Interior

  • Jason, I will work on this when I return home tomorrow.


    -Fred-

    65 Koupe early San Jose Phoenician Yellow 4 speed
    66 GT Koupe Dearborn Blue 4 speed
    66 KGT San Jose fastback pony interior Silver Frost 4 speed
    64 Falcon sedan delivery 289 4 speed
    65 Ranchero 289 4 speed
    66 Corvette roadster 427/425 4 speed

  • Jason, This will get more confusing as all of this unfolds. There was never a C5AZ 6A666 B part number so we can eliminate that. The C5AZ 6A666 A and the C5AZ 6A666 A1 are the same and the A1 suffix was never recognized in the Ford price book. I have seen other part numbers with a 1 added after the suffix that are in the same category of meaning nothing in regards to the actual part number. Your concern should NOT be with the Ford part number but rather with the Ford engineering number which is sometimes stamped, stenciled, cast into or otherwise on the actual part. Many Ford parts do not have engineering numbers. The engineering numbers rarely ever are the actual part number but rather a reference within Ford as to where the parts use originated. In the case of these PCV valves the number you are seeking is a C5AE 6A666 A. The 1966 Ford parts catalog also calls for the C5AZ 6A666 A to have an engineering number of C5AE 6A666 B as an alternate. The 1965 Ford bound parts book lists the same C5AZ 6A666 A valve having a C5AE 6A666 C engineering number. Although not listed in the catalog, the C5AZ 6A666 A valves have AC SPARK PLUG stamped on it as well. I have not actually seen the C5AE 6A666 B engineering number on a valve but they do probably exist.


    The former paragraph is what is listed in both the 1965 and 1966 Ford parts bound books that come out at the beginning of the model year. They only list the parts as they were available at the beginning of the model year. Things like parts for a 1965 GT model are NOT in there as they came out later in the model year.


    Now for more fun, I have a Ford MPC that has purposely not been updated since 1970. This catalog shows a lot of part numbers that were eliminated in the 1975 final edition when some parts were long obsolete, etc. That book shows a C6AZ 6A666 A part number with a C6AE 6A666 B engineering number as the C5AZ 6A666 A valve was replaced by the C6AZ 6A666 A valve some time in the 1966 calendar year, not necessarily, the model year 1966. When did this actually happen? I am unclear however I can tell you that the two valves have a distinctively different appearance from each other beginning with the natural finish of the C5AZ 6A666 A valve and the black finish of the C6AZ 6A666 A valve. The C5AZ 6A666 A valve has a hex on it where the C6AZ 6A666 A valve is round.


    Are you confused yet?


    -Fred-

    65 Koupe early San Jose Phoenician Yellow 4 speed
    66 GT Koupe Dearborn Blue 4 speed
    66 KGT San Jose fastback pony interior Silver Frost 4 speed
    64 Falcon sedan delivery 289 4 speed
    65 Ranchero 289 4 speed
    66 Corvette roadster 427/425 4 speed

  • Haha, not confused at all because all this information is all lining up with what I currently had found (even the AC Spark Plug stamping). I've been told the round black finish one C6AZ 6A666 A was the correct one for my car, but also been told the hex natural finish C5AZ 6A666 A valve was correct for my date car as well, so I guess at this point no one really knows and could use either, obviously the hex one is way easier to find, only seen one of the round black finish one once in my travels and it was used. So I guess I'll be looking for the one with the stamping. I did find this one that seems to align with what we think to be the correct one, but pretty beat and pricey for my application and what I'm looking for... do you agree this is probably the correct one?


    Thanks again Fred,


    Jason


    https://www.ebay.com/itm/65-66…a849dfbfff5f1cc%7Ciid%3A1

    February 10th 1966 - San Jose - Factory GT K-Code Automatic, Candy Apple Red Fastback, Black Standard Interior

  • Jason, I am happy that you are sharing my confusion on this subject. I mentioned in my first post on this thread that I have several NOS ones of the C5AE version. I still have them even after a whole day has passed by. Please give me a call.


    -Fred-

    65 Koupe early San Jose Phoenician Yellow 4 speed
    66 GT Koupe Dearborn Blue 4 speed
    66 KGT San Jose fastback pony interior Silver Frost 4 speed
    64 Falcon sedan delivery 289 4 speed
    65 Ranchero 289 4 speed
    66 Corvette roadster 427/425 4 speed

  • Will do, I'll give you a call a little later in the day, appreciate all your help as always...

    February 10th 1966 - San Jose - Factory GT K-Code Automatic, Candy Apple Red Fastback, Black Standard Interior

  • Whenever you see a suffix after the last letter of the engineering number, such as A1 and A2, it means two different vendors are supplying a part under the same part number. The appearance of the part between A1 and A2 can be quite different. On rare occasions, the A and A1 on the part number might occur, but I have not seen it listed this way in the MPC, only on the actual box of the part. There are also occasions where instead of the A1 and A2 on the engineering number, it will have a different letter, such as A, B, and C. For example, C5AZ-6A666-A could be marked C5AE-6A666-A or C5AE-6A666-B. C5AZ-6A666-A1 could be marked C5AE-6A666-A, C5AE-6A666-B, or C5AE-6A666-C.


    And it gets more fun. C6AZ-6A666-A was marked C6AE-6A666-B. But, it was for the big blocks in 1966, not the 289. Then in 9-67 (near 1968 production), the C6AZ-6A666-A part number replaced C5AZ-6A666-A. Since these valves were supposed to be replaced every 12,000 miles, the C6AE-6A666-B valves were getting installed on the earlier 289s. And, although Ford did not show different engineering numbers under the C6AZ-6A666-A part number, there were at least two I found -- C6AE-6A666-B1 and C6AE-6A666-B2. Both were different designs, each from a different company.


    So, what should you use? You are safe with a C5AE-6A666-A, C5AE-6A666-B, or C5AE-6A666-C marked valve.

  • Whenever you see a suffix after the last letter of the engineering number, such as A1 and A2, it means two different vendors are supplying a part under the same part number. The appearance of the part between A1 and A2 can be quite different. On rare occasions, the A and A1 on the part number might occur, but I have not seen it listed this way in the MPC, only on the actual box of the part. There are also occasions where instead of the A1 and A2 on the engineering number, it will have a different letter, such as A, B, and C. For example, C5AZ-6A666-A could be marked C5AE-6A666-A or C5AE-6A666-B. C5AZ-6A666-A1 could be marked C5AE-6A666-A, C5AE-6A666-B, or C5AE-6A666-C.


    And it gets more fun. C6AZ-6A666-A was marked C6AE-6A666-B. But, it was for the big blocks in 1966, not the 289. Then in 9-67 (near 1968 production), the C6AZ-6A666-A part number replaced C5AZ-6A666-A. Since these valves were supposed to be replaced every 12,000 miles, the C6AE-6A666-B valves were getting installed on the earlier 289s. And, although Ford did not show different engineering numbers under the C6AZ-6A666-A part number, there were at least two I found -- C6AE-6A666-B1 and C6AE-6A666-B2. Both were different designs, each from a different company.


    So, what should you use? You are safe with a C5AE-6A666-A, C5AE-6A666-B, or C5AE-6A666-C marked valve.

    Excellent response, Bob!!


    -Fred-

    65 Koupe early San Jose Phoenician Yellow 4 speed
    66 GT Koupe Dearborn Blue 4 speed
    66 KGT San Jose fastback pony interior Silver Frost 4 speed
    64 Falcon sedan delivery 289 4 speed
    65 Ranchero 289 4 speed
    66 Corvette roadster 427/425 4 speed

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