I'm sure there are other forum subscribers who can do a better job of answering this question than I, but until they do, I'll take a stab at it.
The first letter (C) refers to the decade of manfufacture, beginning with A for the 1940s. So C means the part was built in the 1960s. The second digit (6) refers to the year of the decade in which the part was designed and built. So the part was manufactured in 1966. The third letter refers to the "Product Line." The letter O means the part was built for use on the Fairlane/Torino/LTD product series. The last letter (E) identifies the Internal Division, in this case the Engineering Division.
The last four digits (9430) is the actual part number. There are zillions of these, so you'd need a Ford parts manual or interchange manual to identify the specific part. But from decoding the prefix (C6OE) we know the part was designed and built in 1966 for use on a Fairlane, Torino or LTD.
You'll find more information on part number decoding in TCCN's Encata on-line classic Cougar encyclopedia.