In 1968, Leonard would begin the season in the #9 Vel's Ford Sales Morris-Ford for Vel's Parnelli Jones Racing. Leonard would finish in 3rd place at the Stardust 150 at Stardust International Raceway; this would end up being his best finish of the season. At the Indianapolis 500, Leonard would begin to drive for STP-Granatelli Racing first to drive the #40 STP Oil Treatment Granatelli-Pratt &amp; Whitney Canada PT6 but he would crash that car in practice. As a result, he would drive the #60 STP Oil Treatment Lotus 56-Pratt &amp; Whitney Canada PT6 in place of the injured Jackie Stewart. During qualifying Leonard would qualify on the pole position at a new track record speed of 171.599 mph. During the race Leonard would lead for 31 laps, battling with Bobby Unser and Lloyd Ruby for much of the race. When the race got restarted on lap 191 Leonard's fuel shaft broke. His teammate Art Pollard, who had been running three laps behind at the time, had the same thing happen to him. Leonard would finish in 12th place.