The 1978 Southern 500, the 29th running of the event, was a NASCAR Winston Cup Series racing event that took place on September 4, 1978, at Darlington Raceway in Darlington, South Carolina. By 1980, NASCAR had completely stopped tracking the year model of all the vehicles and most teams did not take stock cars to the track under their own power anymore. Only manual transmission vehicles were allowed to participate in this race; a policy that NASCAR has retained to the present day.