The Mustang I was designed by John Najjar in late 1961 and based on the 'Cardinal' project. A V-4 front wheel drive sports/economy vehicle. The vehicle was to be produced in Germany and imported into the US and sold through Ford dealers as an entry level economy car. John's design a mid-engine two seat vehicle was built and toured the US, but Ford management believed that a small mid-engine rear wheel drive, two seat vehicle, with a limited trunk would not have the sales and volume potential of a larger four seat "Sporty" vehicle they had in mind. The Cardinal project was abandoned for the US and Ford management then focused on the Mustang II (not related to the 1974 Pinto based Mustang II) concept for further research, development and market testing.

The Cardinal was ultimately tooled and produced in Germany as the Taunus and over 2.5 Million units were sold in the European market between 1962 and 1970. It's transaxle, steering and front wheel drive system was adapted by other European car companies including Volkswagen when the Beetle production was ending and the front wheel drive Golf/Rabbit was to replace it.