heads, 34 (0 and 350 with iron heads) went to a four-bolt-per-cylinder pattern. At introduction, Buick's 215 was rated at 4400 rpm. This was raised soon after introduction to at 4,600 rpm. of torque was produced at 2,400 rpm with a Rochester 2GC (DualJet) two-barrel carburetor and 8.8:1 compression ratio. A mid-year introduction was the Buick Special Skylark version, which had 10.0:1 compression and a four-barrel carburetor, raising output to at 4,800 rpm and at 2,800 rpm. For 1962, the four-barrel-equipped engine's compression ratio was increased to 10.25:1 and horsepower to at 4,800 rpm and at 3,000 rpm. The two-barrel engine was unchanged. For 1963, the four-barrel was bumped to 11.0:1 compression and an even at 5,000 rpm and at 3,200 rpm, /cu in. The great expense of the aluminum engine led to its cancellation after the 1963 model year. The engine had an abnormally high scrap ratio due to hidden block-casting porosity problems, which caused serious oil leaks. Another problem was clogged radiators from antifreeze mixtures incompatible with aluminum. It was said that one of the major problems was because the factory had to make extensive use of air gauging to check for casting leaks during the manufacturing process and was unable to detect leaks on blocks that were as much as 95% complete. This raised the cost of complete engines to more than that of a comparable all cast-iron engine. Casting-sealing technology was not advanced enough at that time to prevent the high scrap rates. The 215's very high power-to-weight ratio made it immediately interesting for automobile and boat racing. Mickey Thompson entered a stock-block 215-powered car in the 1962 Indianapolis 500. From 1946-1962, there had not been a single stock-block car in this race. In 1962, the 215 was the only non-Offenhauser-powered entry in the field. Rookie driver Dan Gurney qualified eighth and raced well for 92 laps before retiring with transmission problems. Surplus engine blocks of the Oldsmobile F85 version formed the basis of the Australian Formula One Repco V8 used by Brabham to win the 1966 Formula One world championship, although only the earliest engines had any Oldsmobile components. The majority of Repco RB620 engines were cast and built in-house at Repco. Rights to these engines were purchased by the British Rover Company and used in the 1967 Rover P5B that replaced the 3 L straight six Rover engined P5. Throughout the years, the Rover