When NASCAR was first formed by France in 1948 to regulate stock car racing in the U. S. , there was a requirement that any car entered be made entirely of parts available to the general public through automobile dealers. Additionally, the cars had to be models that had sold more than 500 units to the public. This is referred to as “homologation”. In NASCAR’s early years, the cars were so “stock” that it was commonplace for the drivers to drive themselves to the competitions in the car that they were going to run in the race. While automobile engine technology had remained fairly stagnant in World War II, advanced aircraft piston engine development had provided a great deal of available data, and NASCAR was formed just as some of the improved technology was about to become available in production cars.  Until the advent of the Trans-Am Series in 1967, NASCAR homologation cars were the closest thing that the public could buy that was actually very similar to the cars that were winning national races.