Few car people haven’t dreamed about uncovering a factory prototype. It happens (and more often than one might imagine). The question then becomes, what’s it worth? How do you put a value on a one-of-one? Here are a few things to think about:
1. Significance of the car that the prototype led to: It is axiomatic that at Shelby Cobra prototype would be more valuable than a Cosworth Vega prototype.
2. Character and magnitude of the differences between the prototype and the production car: The best example of this is the Jaguar E-type prototype E2A. E2A retained many of the design features of the Le Mans-winning D-type race car and was very much an obvious one-off. It also had an illustrious race history via the famous Briggs Cunningham team. It recently sold for $947,000, or about six times the price of a concours-condition E-type roadster, one of the most iconic sports cars of all time. When the differences between the prototype and a production example are far more subtle, there is less value.
3. Any competition history: See above. Very often prototypes are famously raced and used as test beds for future competition efforts. This greatly enhances the value of the car.
4. Compelling back story: Again, getting back to E2A, there is a compelling back story. Having evaded disposal by Jaguar, E2A wound up in the hands of one of the most famous privateer racers and sportsmen of the 1950s, Connecticut-born Briggs Cunningham.
5. Comparables: Although it’s sometimes not obvious, there is almost always a comparable.