1960s adapted superchargers with a custom camshaft to feed intake air in through the exhaust ports; the larger intake ports became the exhaust outlets. 425 The was produced from 1963 to 1966. The largest-displacement version of the Nailhead, it began as an option on the 1963 Riviera, and was later available on the Wildcat and Electra models. The 1964 and 1966 Rivieras used the 425 engine as standard equipment. Mounted on a trolley, Buick 425s were also used as starter motors for the SR-71 Blackbird supersonic jet. Four-barrel carburetion was standard on the basic 425, called the Wildcat 465 for the torque (as measured in lb-ft) it developed. The Super Wildcat (Regular Production Option {RPO}-coded Y48) was available on the 1965 Riviera Gran Sport and 1966 Wildcat GS, which included two four-barrel carburetors and matching intake manifold. Coded "MW", these parts were delivered in the car's trunk for dealer installation. Toward the end of the 1966 model year, around May 1966, Buick offered the Super Wildcat 465 with factory-installed dual four-barrel Carter AFB carburetors as an "MZ" option. Only 179 of the 1966 Riviera GS cars were built with the MZ package. Buick small block 215 See also Rover V8 engine In 1961, Buick unveiled an entirely new small V8 engine with aluminum cylinder heads and cylinder block. Lightweight and powerful, the aluminum V8 also spawned a turbocharged version, (only in the 1962–63 Oldsmobile Jetfire), which together with the turbocharged Corvair Spyder, also introduced in 1962, were the first ever offered in passenger cars. It became the basis of a highly successful cast iron V6 engine, the Fireball. The all-aluminum V8 engine was dropped after the 1963 model year, but was replaced with a very similar cast-iron block, aluminum head version for one year, and then in all-iron versions. Bore spacings for all variants of the SBB are . History GM experimented with aluminum engines starting in the early 1950s. Aluminum Company of America (ALCOA) was pushing all automakers to use more aluminum. An early-development supercharged version of the V8 was used in the 1951 Le Sabre concept car, and the 1953 Buick Roadmaster concept car, and work on a production unit commenced in 1956. Originally intended for displacement, Buick was designated by GM as the engine design leader and decided to begin with a larger, size, which was deemed ideal for the new senior compact cars introduced for the