Oh, don't get me started on Ford's cumbersome and convoluted parts system numbering. While it has benefits, there are also pitfalls. Luckily, people don't restore many newer Fords as they use more than one numbering system.
Ford numbers are not necessarily intelligent numbers when it comes to the end user. In fact, by part number engineering standards, the consensus is the most effective numbering system lands about 6 or 7 characters max, and all numerical. This was concluded with the parts jockey at the counter in mind because studies found the longer the number, the more inaccurate the short-term memory would be (obviously). Because of the ripeness for errors, engineering numbering experts do not recommended a part numbering system with any significance. Longer part numbers usually means part numbers need to be written down. And longer p/n sequences needed entry into the computer systems. And when doing that, error rates rise.
Ford part numbers can give you lots of parts info if you dig for it, but if you're not a Ford parts manager, you need your book of numbering systems to decipher what they mean. If you find new or NOS parts still in the sealed package at a swap meet, have you memorized the "intelligent" part numbers to determine what you are looking at? Or do you need to carry your decoder ring? Recall that OEM's were not in any way worried about someone restoring their car 50 years later. They were intended for the mechanic at the dealership to get the right part for the car they were fixing as quickly as possible. Most of us wrench-turners use descriptions far more than part numbers.
According to Tex Criqui, a GM engineer that used to be GM's Manager of Standards, Records and Tech Documentation and prior to that Manager of Engineering Standards (part of the job was assigning part numbers), GM wanted him to design a "smart" system in the '90s. They could never land on one. He said the simplest and most effective was basically what they've always done- a numerical, sequential style with no real meaning, the string to be short as possible, and only used for tracking the part.
About the only thing decipherable on GM part numbering systems is which side of the car they're used when you have a RH and LH part, is that they generally use an ODD number for a LH part, and an EVEN number for a RH part. Ford uses this same designation style when assigning LH and RH numbers for their older basic number. Not sure if that holds on their newer system.
And GM even numbers crap weird so you can't even guess where or what the next part number is. Example: The A.I.R. U-bend hose on the diverter valve on a 307 is p/n 22506641. Then you find part 22506643. Well, you might THINK that's the p/n for another A.I.R. component. No. It's the bright hood push-on molding at the rear of the hood. WTF?
Now with that, GM does tend to change part numbers when supply vendors are changed, although that doesn't always happen. And notice, sometimes the same part number is used for YEARS AND YEARS. One notable example is the cotter pin for the front spindle nut (and probably other places) part number. It's been p/n 103387 for seemingly forever, and is still in use today. Ford doesn't do that. I think somewhere around the late 90s or early 2000's, Ford went to another numbering system which only gives you the first year it was used, not for any specific year. Yay!!! More sh*t to decipher! I'll never understand Ford numbers. It's bad enough dealing with GM part numbers.