The 47th International 500-Mile Sweepstakes was held at the Indianapolis Motor Speedway in Speedway, Indiana on Thursday, May 30, 1963. Parnelli Jones took his only Indy 500 win despite his car (nicknamed "Calhoun") spewing oil from a cracked overflow tank for many laps, which allegedly caused at least one driver to spin and crash. USAC officials put off black-flagging Jones after car owner J. C. Agajanian ran down pit lane and convinced them that the oil leak was below the level of a known crack and would not leak any further. Lotus owner Colin Chapman, whose English-built, rear-engined Lotus-Ford finished second in the hands of Scotsman Jim Clark, accused USAC officials of being biased towards the American driver and car.