This is not my listing, I just saw it on ebay, bewlow is their description: I didn't want it to get buried in the classified section in case anyone is looking:
NOS GM PART#3916621 COLD AIR COWL PLENUMS AIR DUCT ASM .THIS IS NOT A REPRODUCTION.THIS IS VERY RARE IN ORIGINAL GM BOX.HAS NEVER BEEN INSTALLED.WILL FIT 67-68 CAMARO Z28.WILL ALSO FIT 64-69 CHEVELLES,EL CAMINO,IMPALAS,PONTIACS.SERIOUS INQUIRES ONLY!
https://www.ebay.com/itm/223338970324?ul_noapp=true
Paul