45: Ford Mustang II
The Mustang II was based on the Ford Pinto, and a lot of the issues with its design came to light. We’re not sure why Ford would base their hot-selling pony car on the Pinto, but they did. The Pinto-based Mustang was lambasted by consumers who questioned the safety and build quality of the car (via Motor Trend).

The Pinto-based Ford Mustang II was also one of the slowest Mustangs in history. This was at a time when automotive manufacturers had to meet new emissions laws. Let’s just say the Pinto-based Mustang was not winning any races this time around.