Ford 7-Litre
What exactly was the Ford 7-Liter? It was a car supposed to be slotted between the Mustang and the Thunderbird. The 7-Liter was a forgotten luxury sports car that many have already forgotten about. The entire production run only consisted of 11,000 models, making the car extremely rare (via Hemmings).
Its 428 horsepower output was respectable at the time, but the car was large and the performance was barely felt. The Ford 7-Liter was the product of a company assuming what the consumer wanted, instead of learning the marketplace. Incidentally, the 7-Liter was only manufactured for a single production year.