48. Buick Riviera GS
Buick conceived the Riviera as a personal luxury coupe. But they managed to turn it into a proper luxury muscle car with the GS package. in 1965, Gran Sport or GS featured revised suspension, a bigger 425 engine, and a host of other performance upgrades (via Schmitt).
However, in this version, the Rivera was a true world-class automobile. It delivered 360 HP with 0-60 acceleration times of 7.9 seconds, figures that were better than most sports cars of the period.