- Official Post
Here is an Ebay auction for a really nice used C5ZZ 18491 A defroster plenum by Ebay member "mblackmd" with a starting bid of $1.00:
1964 1/2-68 Mustang & 65-68 Shelby Original heater plenum. Beautiful shape. One of the nicest I have ever seen.
1964 1/2-68 Mustang & 65-68 Shelby Original/Used Heater Plenum. Almost NOS | eBay
-Fred-