7. Buick Riviera GS
They conceived the Riviera as a personal luxury coupe. But Buick managed to turn it into a proper luxury muscle car if you optioned for the GS package. in 1965, Gran Sport or GS featured revised suspension, a bigger 425 engine, and a host of other performance upgrades.
However, in this version, the Rivera was a true world-class automobile. It delivered 360 HP with acceleration times of 7.9 seconds. And that was better than most sports cars of the period.