Ford Hood Scoop

[Speedrx]

Bill,

It primarily signifies the year of the vehicle but in some cases, parts are carried over another year. There is usually a separate date stamp on the part for when it was built.
I have seen C8 and C9 parts on 1970 Mustangs so you can assume it was on a 1971 and possible used for a few more years.
If someone has a Ford Master Parts catalog, they can look it up and get the exact years and application.

I am almost certain it is a hood scoop for a 1971 Mercury Cougar GT or 429.