Ford Pinto
The Ford Pinto was both revolutionary and cautionary for domestic automakers. The compact car proved to be one of the best-selling Ford’s of all time, but the build ended up being questioned. The optional power and performance that the Pinto offered were one of the best selling points of the car. The Pinto was quite fast and it proved to be one of the first sleeper cars on the market (via Car Gurus).
Unfortunately, a faulty rear fuel tank design caused the car to be engulfed in controversy, and Ford ended up losing billions of dollars. Nevertheless, the Pinto is one of the most notable sleeper cars on the market from this era. The unique design was unlike anything else at the time, and Ford caused a stir and gave the Japanese automakers a run for their money.