409

A 409-cubic-inch (6.7 L) version was Chevrolet's top regular production engine from 1961 to 1965, with a choice of single- or dual-four-barrel carburetors. Bore and stroke were both up from the 348 at 4.312 in (109.5 mm) by 3.50 in (89 mm). On December 17, 1960, the 409 engine was announced along with the Impala SS (Super Sport) model. The initial version of the engine produced 360 hp (270 kW), with a single-four-barrel Carter AFB carburetor. The same engine was upped to 380 hp (280 kW) in 1962. A 409 horsepower (305 kW) version of this engine was also available, developing 1 hp per cubic inch with a dual-four-barrel aluminum intake manifold and two Carter AFB carburetors. In the 1963 model year, output reached 425 hp (317 kW) at 6200 rpm with the 2X4 setup, 11.25:1 compression and a solid lifter camshaft. This engine was immortalized in the Beach Boys song titled "409". The engine was available through mid 1965 when it was replaced by the 396-cubic-inch 425 hp (317 kW) Mark IV big-block engine. In addition, a 340 hp (250 kW) version of the 409 engine was available from 1963–1965, with a single-four-barrel cast-iron intake mounting a Rochester 4GC carburetor, and a hydraulic-lifter camshaft.