The cause of death was not released, but Shelby's health had been in decline for years, The Wall Street Journal reported Saturday.
As far back as 1960, Shelby finished third at Laguna Seca Raceway in Monterey, Calif., in a race in which he was slowed down by having to place nitroglycerin pills underneath his tongue to stave off a possible heart attack, the Los Angles Time's obituary said.
He also survived a kidney transplant, a heart transplant and seven marriages. He lived in the fast lane, the Times said.
"Everything he touched was legendary," said Leslie Kendall, curator of the Petersen Automotive Museum in Los Angeles.
Shelby, whose name is associated with performance cars at Ford, Chrysler and General Motors, "is one of the most recognized names in performance car history, and he's been successful at everything he's done," said Edsel Ford II, great-grandson of Henry Ford.
Perhaps his most famous muscle car for the U.S. market is the Shelby Mustang.
For the native Texan, undersized was not his style. The 2013 Ford Shelby GT500 Mustang, sports the most powerful production V8 in the world with 650 horsepower.
His career on the track, which he said was merely hands-on schooling for his career as a designer, made him one of the most recognized figures in sports. He was Sports Illustrated magazine's driver of the year in 1957 for the second time after winning 19 consecutive races.
He was the co-driver of the Austin-Martin that won the 1959 World Manufacturing Championship with a victory a the 24-Hours of LeMans race.
He once drove a Ferrari in a a 12-hour race in Sebring, Fla., with a cast on an elbow and his hand taped to the steering wheel.
He placed second in that one.
It turns out, all along, the three-time national champion had other plans.
"I had a lot of fun driving race cars, but it wasn't my No. 1 priority. Driving race cars was an avenue for me to learn how to build my own car, and that was my ambition all along," he said in an interview in 2006.