around 1200 orginal cobras including all models(260,289,427,428) approx 347 big block cars
And 12,000 Shelby Mustangs compared to about 18,000 Gen 1 and 2 Vipers. Only a fraction of the Shelby Mustangs are worth big money. At last years BJ Auction I saw an a/t GT500 go for around 50k. That's less than a Challenger T/A "Recreation" sold for.
I think you need to compare the Viper to other exotics. The Countach has been gone for over 15 years and you can still pick one up for less than the new price of 85k. The Testarossa, with a production of around 9,000 units was 125k new and you can pick one up for a little over half that.
The better comparison is the Ferrari 328. Not a money pit to keep up like the 12 cylinder Ferrari and Countach, and cost in the low 60s new. These can be found for a little over 50k in nice shape today. Not much of a performer by todays standards but it has the Ferrari cachet and the Magnum PI look.
The cars that bring the huge money at auction are the nearly unique models and except for a few color combos all Vipers are almost the same car. 1992s should always be worth the most, then maybe the first year GTS in b/w, the ACRs, then maybe the FE models. Since creampuff vs forged piston is really a forced induction thing which won't mean a lick to a collector the ABS cars might turn out to be more valuable but then they buy these things to hoard not to drive so maybe not.
I notice the [******] cars don't have great resale compared to stockers. They are worth more, but the price difference doesn't equal the new purchase price difference.Tuner Vipers don't seem as highly regarded as some of the tuner Vettes come auction time.
Maybe once the generation of kids who grew up idolizing the Viper as the ultimate performance car become rich 50 something collectors it will change. I haven looked at other tuner supercars like the Ruff Porsche to see how they resell.