According to Wikipedia:
Early Winston Cup career
Dale Earnhardt began his Winston Cup career in 1975, making his first start at the Charlotte Motor Speedway in North Carolina in the longest race on the Cup circuit, the World 600. Earnhardt drove an Ed Negre Dodge Charger(# 8 ) and finished 22nd in the race, one place ahead of his future car owner, Richard Childress. Earnhardt competed in 8 more races until 1979, when he joined Rod Osterlund Racing, in a season that included a rookie class of future stars - Earnhardt, Harry Gant and Terry Labonte.