I also a found an old K&N filter that just needs to be cleaned. The only Identifying that I could find is FD40E8 but this number is not on K&N's website but did find
Similar Filter. It is the same style but I think the inlet is 3 or 3 1/2 inches. I used it for a homemade cold air kit for an old Chevy truck/Avalanche.
I will sell it for $30.