AAA Stock Car Rules

This is an interesting item on the American Automobile Association's (AAA) rules for race cars in 1909. The article appeared in the Indianapolis Star on August 15, 1909. The key issue of the day was to rule on what cars were considered "stock" versus purpose-built as race cars. The latter category was frequently derided as "freak" cars that contributed little to demonstrating the value of a given manufacturer's product.
 
The article divides the classifications into "stock chassis" and "stock." Two paragraphs are devoted to listing specific modifications that can be made to a race car using a stock chassis as opposed to an almost completely stock motor vehicle. The key rule for the stock classification was that at least 25 units of the product had to have been manufacturered. It is unclear from the article if there is an additional classification for pure, purpose-built race cars. This judgment on distinction was particularly important as this article was published the week of the first automobile races at the Indianapolis Motor Speedway.