The news comes after NASCAR Vice President John Dodson in April said Yarborough "was not doing well" and asked fans to keep him in their prayers.

The South Carolina native won the NASCAR crown in 1976, 1977 and 1978, making him one of only two drivers in the sport's history to win three consecutive championships.

He claimed 83 wins and 319 top-10 finishes during his NASCAR career that spanned from 1957 to 1988.

The three-time Driver of the Year award winner won the Daytona 500 in 1968, 1977, 1983, 1984 and was inducted into the NASCAR Hall of Fame in 2012.

“Cale Yarborough was one of the toughest competitors NASCAR has ever seen,” said NASCAR Chair and CEO Jim France in a statement. “His combination of talent, grit and determination separated Cale from his peers, both on the track and in the record book. He was respected and admired by competitors and fans alike and was as comfortable behind the wheel of a tractor as he was behind the wheel of a stock car."

Yarborough's NASCAR obit includes his actual victories in racing as well as yarns spun about the NASCAR legend "with varying degrees of truth behind it." Tales included that he survived a lightning strike, flew and landed an airplane without training and once wrestled an alligator in a swamp.

Yarborough was at the center of an iconic NASCAR moment when in the final lap of the 1979 Daytona 500, Yarborough and Donnie Allison crashed while racing for the lead.

The drivers emerged from their cars and exchanged blows in a fight that was broadcasted on television.

"I think it opened the world's eyes to stock car racing. I mean, they said, 'These guys are for real. They'll get out and duke it out if they have to,'" Yarborough said years later, according to Yahoo Sports.

"The only regret I have is that it wasn't a better fight."

William Caleb "Cale" Yarborough was born on March 27, 1939, to a tobacco farmer, in the tiny community of Sardis, just on the outskirts of Timmonsville, South Carolina. The oldest of three boys, Yarborough was just 10 years old when his father died in a plane crash.

A star athlete during high school, Yarborough went on to play semi-pro football for four seasons. He was also a Golden Gloves boxer for a period.

Yarborough made his racing car debut in 1957 at the Southern 500.

Pete Hamilton, a rival of Yarborough during their racing careers, recalled a race at Michigan International Speedway in 1970 where Yarborough took the lead from him in the final two laps before beating him by 0.3 seconds to the finish.

Hamilton said what set Yarborough apart was his toughness.

"We banged fenders all day long. At the end, he got paid for first," Hamilton said, according to Yahoo Sports.

"It was his determination. In those days, we didn't have side glasses or window netting, so you could look over at the other guy going down the straightaway.

"I remember looking over at Cale. Even at 185 miles per hour, you could see the determination in his eyes."

After retiring in 1988 he owned Cale Yarborough Motorsports, which competed in the Cup Series until 2000, and several agricultural businesses.

NASCAR greats Dale Earnhardt Jr., Richard Petty and Jimmie Johnson posted their condolences to his family online early on Sunday.

Earnhardt wrote, "Sad news about the passing of Cale today. A legend behind the wheel for sure."

Petty wrote that Yarborough's rivalry with him will always "be a part of NASCAR history."

And Johnson wrote that "Yarborough was my childhood hero...and the legacy of Cale Yarborough will forever live on."

Yarborough is survived by his wife Betty Jo, who he married in 1961, and his three daughters.