Ford Part Numbers, Casting Numbers, and Date Codes
Decode Ford, Lincoln, and Mercury part numbers, casting numbers, engineering and service parts, and date codes
Ford kept track of the various parts and castings in its inventory by assigning each item its own unique alphanumeric identification number. These numbers provide a lot of information to those who are familiar with what the numbers mean. The unique identifier is a series of numbers and letters that are put in a specific sequence, and the location of the digit determines what that digit designates. Information commonly provided by part numbers includes the decade during which the part was designed or manufactured, the year of the decade the part was designed or manufactured, the car line the part was originally designed for, the engineering department originally responsible for the design, the basic part number, and the changes made to the original design.
What can be confusing about these numbers is that a part designed for one year might actually be used for several years, or a part designed for one car line might be used on other lines as well. For instance, a part originally designed for a 1964 Ford could often be found on a 1964 or 1965 model Thunderbird, Mercury, or Lincoln as well. It is actually quite common to find parts originally designed for Thunderbirds on Lincolns, and Falcon parts on Mustangs. In order to spread out the costs of designing and manufacturing a part, Ford used parts on different models.
The Ford part number on the box shown at left is on the top line: B8A-9431-A. Other information indicates it was an Engine Engineering Division design, weighs 9 pounds, provides information on the quality control inspection, and the date packed.
A typical Ford part number looks like this:
Here's how this number is decoded:
C = Decade of design (1960's)
This basic wheel was used on Thunderbirds from 1965-1967. While it was possible to use a wheel from a 1964 Thunderbird on the rear of a 1965 Thunderbird, that wheel would not fit on the front wheels, and as such was unacceptable for use as a spare tire. In 1968, the Thunderbird received a new front disc brake design, and with it a new wheel, listed at right.
A similar Ford part number looks like this:
Let's break down the Ford part number on the box shown at left:
It should be noted that the SW-653 number also identifies this part correctly, and is an additional reference number used by Ford and its suppliers. It is also a unique number, and changes due to specific equipment options on a given vehicle.
According to the parts book, this switch fits a 1968 Ford Thunderbird with tilt steering wheel. There were multiple revisions to this switch, so there is a notation that I.D. Markings E, F, G or H as the suffix digit at the end of the part number are also applicable. This could mean revisions to the part or multiple manufacturers supplying the part to Ford.
Another part is provided for 1968 Ford Thunderbirds with fixed steering wheels, and it is C8MY-7A247-A (SW-649) with revision I.D. Markings of F, G, H, J or K. Note that this switch was originally designed for the Mercury Division, due to the "M" as the third digit in the part number. This indicates the part was originally designed for a 1968 Mercury, and illustrates how parts crossed over from one line to another, across divisions, and the equipment provided on a particular vehicle often determined that different parts were used.
In order, here is what each digit in a Ford part or casting number represents:
DIGIT #1—DECADE OF MANUFACTURE:
A - 1940
DIGIT #2—YEAR OF THE DECADE:
0 - 1960, 1970, etc.
Example: B8 = 1958; C1 = 1961; C9 = 1969; D9 = 1979, etc.
DIGIT #3—CAR LINE:
A = Ford (from 1958; Galaxie, Custom, LTD)
DIGIT #4—ENGINEERING OFFICE RESPONSIBLE FOR ORIGINAL DESIGN:
A = Light Truck Engineering Division
DIGITS #5-9—BASIC PART NUMBER:
This series of numerals denote the actual part description, i.e., wheel assembly, relay assembly, etc. It is possible a letter or two may also appear within the series of numerals. The basic part number is still the same, however if the alphabetical letters are disregarded.
DIGITS #10-12 (SUFFIX)—DESIGN CHANGE:
Normally an alphabetical letter, with the original design being designated by the letter "A". A first revision to the original design would normally be noted with a "B", although sometimes this digit identifies a completely different component, even though the basic part is the same. For instance, different engine displacements and designs. Parts finished in different colors can be identified by their suffix numbers as well. For instance, the Simulated Styled Steel Wheel Covers for a 1969 Ford Thunderbird carry the basic part number C9SZ-1130D, followed by -26B for Brittany Blue color, 13D for Candyapple Red color, etc.
ENGINEERING VS. SERVICE PART NUMBERS
It should be noted that Ford part numbers are divided into two main categories: engineering part numbers and service part numbers. When a part is first designed, engineering assigns it an alphanumeric part number, such as C5SZ-1005-A. If the part is later completely redesigned, a new part number is assigned to it by engineering, to differentiate between the two parts, for instance C8AZ-1007-E. Both are wheel assemblies, but they have very different applications.
When the part is released as a service part, the service part number assigned to the part is likely to initially be the same as the engineering part number. Small revisions that don't affect compatibility - such as a change in suppliers - usually result in the suffix changing on the service part number to indicate the design change level. Service part numbers are normally listed on the packaging the part comes in, whether it be a box, plastic bag, envelope, sleeve, tube, etc. If the part doesn't normally have a package, a label is affixed to the part itself with the service part number. This is why sometimes the part inside the package will have a different suffix showing on it. The part itself bears the original engineering part number, while the box shows the service part number, which represents the different suppliers.
Often the change in design or suppliers (reflected by the alpha character suffix) is to address a reliability or quality issue. So, if you could choose between identical parts, one with an "A" suffix and the other with a "B" suffix, the "B" is usually the best choice. While parts marked with "B" or a suffix that indicates a change would normally fit and work the same as the same part with an "A" suffix, you can't always replace a "B" or "C" suffix part with an "A" part, even though they are basically the same. This could be due to the other components around this part not being compatible with the original "A" suffix part.
Boxed kits sold to dealers may have multiple part numbers on the various components inside the box, and the number on the box itself will be completely different than that of any parts inside the box.
The easiest way to discern if a part is a factory original or service replacement part is to check the fourth digit of the part number. If it's a "Z" it is a Ford Service Replacement part, indicating it has been changed in service during the life of the vehicle.
Some parts may include a date code indicating when the part was manufactured. Date codes are located in various areas, and are normally comprised of 3 or 4 digits.
TYPICAL DATE CODE:
9 = Year (1949/1959/1969/1979/1989/1999) Actual year can be determined by checking the part number of that component for the decade code.
We'll say the part number prefix indicates the decade is the 1960's, so 9A21 is decoded as being built on January 21, 1969. (Yes, we checked...it was a work day.) And sometimes, the date code can be stamped in the wrong order, as in the example shown above. We're going to guess that the "79C" code should have really been "9C7" which would designate a casting date of March 7, 1959, which would be a correct date for that particular part.
MONTH DATE CODES:
A - January