Lotus had suffered the death of driver Jim Clark in a Formula 2 race in Germany. Mike Spence was killed at Indianapolis while testing one of four 56s built. The remaining three cars with Graham Hill, Joe Leonard, and Art Pollard were entered for the race, with Leonard claiming pole position. Unlike the year before, when the STP-Paxton Turbocar easily outperformed the other cars in the race, in the race the turbine cars were relatively evenly matched with the other top contenders, much of which must be attributed to aerodynamics and chassis design and not to the turbine engine. Hill's car crashed, Pollard's car broke down, while Leonard was leading with just a handful of laps to go when the a fuel pump shaft failed. Shortly thereafter, the USAC imposed additional restrictions on turbine cars that essentially removed them from competition. For the second year in a row STP turbine cars had brought innovation to the Indy 500 and had failed to win while leading within a few laps of the end of the race. USAC subsequently banned turbine cars and four-wheel drive completely, but it was unusual enough that Mattel produced a model of the "Lotus Turbine" as one of the popular mass-produced die cast Hot Wheels cars.