However, before the final model hit the market, Ford developed a few concept versions. The first of these concepts was announced 2 years before the launch of the car that would become a nationwide sensation. The concept was unveiled in 1962 at Watkins Glen for the F1 United States Grand Prix and it used a small 1.5-liter V-4 – yeah, a V-4 – engine installed behind the two seats.
Ford named its Mustang project "Allegro," due to many of the engineers and designers working on the concept also being musicians. In order to keep the true nature of the project under wraps, they used musical terms as a code. Of course the Mustang 1 Concept didn’t make it to production, but a number of design cues were used in the final production car.