As a grinning Parnelli Jones rolls into Victory Lane at the end of the "500," his racer bears unmistakable evidence of the oil leak that has caused furious controversy. The near side of the car is oil-grimed and the oil appears still to be seeping from circular bolt (in boxed area) attaching tank to the car's frame. The tank had cracked slightly near the bolt. Formerly inside, the Offie tanks were first put outside by Builder A. J. Watson in 1958 to help cool the oil and increase the cars' cornering stability. Through an intake line and a return line the oil circulates endlessly from tank to engine. The more oil there is the less time any part of it is exposed to engine heat.