6485891 is the generic service replacement air cleaner for '69 Camaro & '70-'71 Chevelle with ducted hood. For some time it was serviced with a chrome lid that was not used in production. Also requires a rubber seal and the metal flange it attaches to. Some applications used an extension to elevate the assembly to meet the hood.
For Camaro it is only correct for 302 and BB applications. It is not identical to the 6485235 unit used in production; that one has a flat bottom and a 90º vent tube. At some point the production unit was revised with a raised bead in the base and a different vent tube; probably September '69.