Hey, Tech, "Thunder Road", my favorite early car movie! And the later one with Jeff Bridges, "Last American Hero", wasn't it? Moonrunners all! Apparently, most stock car drivers were, or at least knew and copied, these guys.
Up here in Canada, they were rumrunners, driving smuggled rum to "Silent Pigs" or illegal bars, using so many McLauglin Buicks that they became known as "Whiskey Sixes" . So I guess there was some whiskey being moved, too.