This would later be remodeled as a four-seat car penned by David Ash and John Oros in Ford's Lincoln–Mercury Division design studios, which produced the winning design in an intramural design contest called by Iacocca.

To cut down the development cost and achieve a suggested retail price of US$2,368, the Mustang was based heavily on familiar, yet simple components. Much of the chassis, suspension, and drivetrain components were derived from the Ford Falcon and Fairlane. The car had a unitized platform-type frame, which was taken from the 1964 Falcon, and welded box-section side rails, including welded crossmembers. The Mustang grew larger and heavier with each passing year, culminating with the 1971 to 1973 models that were far different compared to the original 1964 model. The automaker was deluged with mail from fans of the original car who demanded that the Mustang be returned to its original size and concept.