The Buick Endurance Test was a PR test by the Buick Car Company that occured at Daytona International Speedway in January 1960. Trying to prove that the 1960 Invicta was durable, six professional NASCAR drivers ran 10, 000 miles on the car at speeds always over 120 mph.
10, 000 miles
120.1 mph average
None. General Motors, fearing the Buick stunt made insinuate speeding and not durability, never allowed its Buick brand to publicize the event.