Registrys are a noble goal, but only capture those who know of them, and want to join up. "How many" is a piece of string question, how long is it? :wink:
After 40+ years I'd think one could safely assume less than half still exist. While a bit unique the CS and HCS were never in the class of the Mach 1/Shelby "rare/desireable" cars, and as such I'd bet a lot are still around, but don't look the part anymore with repaints, repairs to damage/rust, etc.
Personally I'd guesstimate if 25% are left in some state to be able to confirm their heritage that would be pretty amazing. Where they all are... all I can say for sure is one is in Brisbane! :wink: