Here is an Ebay auction for a used C6ZF-C carburetor tag by Ebay member "zzzx12" with a Buy-It-Now of $125.00 or make offer:
FORD 1966 289 HiPo C6ZF-C Carb tag
Date June 1966 5th week.
A little rough, but something is better than nothing?
Found in a box of carb parts.
I have attached a photo of the carb that the tag actually came off of.
Came out of 20+ year storage.
Many " Experts" believe it's a reproduction because it doesn't have the registered "R".
But from all the evidence I saw, I personally believe that this was the original tag on that carburetor.
You be the Judge.