* No central registry: Vehicle registration data is handled at the state level, and there's no national database that specifically tracks this combination of features.
* Scrapping and export: Many cars are scrapped or exported over time, making accurate accounting impossible.
* Private sales: Cars are sold privately, outside of official reporting channels.
* Modifications: Some cars might be modified to the point where they aren't easily identified as original IROC-Z models.
You could try to get an estimate by looking at production numbers for the 1987 IROC-Z convertible and then making educated guesses about the survival rate, but that would still be a rough approximation at best. Websites specializing in classic car valuations might offer some clues based on their market analysis, but they wouldn't have precise figures.
