10: 1975-1980 Chevrolet Corvette
American automakers were having a tough time adjusting to new emissions regulations in the late ’70s. The Corvette, once a focal point of performance, suffered from these unfortunate changes (via Edmunds). For five years, the Corvette felt like it was being choked out. The 5.7-liter small-block V8 made a measly 250 hp. That was small potatoes compared to other sports cars at the time or even previous Corvette models.
It ultimately took several years for the brand to recover from these changes. As it stands, the 1975-80 models are some of drivers’ least favorite. Insufficient performance is a real turnoff for most potential buyers. Even restoration can be expensive, and adding a modern engine will be even more.