20 Biggest Cheaters In Sports How They Did It
Smokey Yunick's
NASCAR Auto Racing
Henry "Smokey" Yunick (May 25, 1923 – May 9, 2001) was an American mechanic and car designer associated with motorsports. Yunick was deeply involved in the early years of NASCAR, and he is probably most associated with that racing genre.
NASCAR mandated how much gas the tank could hold, so Smokey inflated a basketball in an oversized fuel tank.
During inspection, they filled up the tank which would appear to conform to regulations. After passing the tech inspection, Smokey would deflate the ball, pull it out of the tank, and fill the regulation-plus-basketball-sized fuel tank for the race - giving him a nice fuel capacity advantage.