Oldsmobile "Rocket V8" engine

The Oldsmobile V8 refers to a series of Oldsmobile engines beginning with the advanced 1949 Rocket which was, along with the 1949 Cadillac V8, the first post-war OHV V8 engines produced by General Motors. Like all other GM divisions, Olds continued building its own V8 engine family for decades, finally adopting the corporate Chevrolet 350 small-block and Cadillac Northstar engine only in the 1990s. All Oldsmobile V8s were manufactured at plants in Lansing, Michigan.

All Oldsmobile V8s use a 90° bank angle, and most share a common stroke dimension: 3.4375 in (87.31 mm) for early Rockets, 3.6875 in (93.66 mm) for later Generation 1 engines, and 3.385 in (86.0 mm) for Generation 2 starting in 1964. The 260 cu in (4.3 l), 307 cu in (5.0 l), 330 cu in (5.4 l), 350 cu in (5.7 l) and 403 cu in (6.6 l) engines are commonly called small-blocks. 400 cu in (6.6 l), 425 cu in (7.0 l), and 455 cu in (7.5 l) V8s have a higher deck height (10.625 in (27.0 cm) versus 9.33 in (23.7 cm)) to accommodate a 4.25 in (108 mm) stroke crank to increase displacement. These taller-deck models are commonly called "big-blocks", and are 1 in (2.5 cm) taller and 1.5 in (3.8 cm) wider than their "small-block" counterparts.

The Rocket V8 was the subject of many first and lasts in the automotive industry. It was the first mass-produced OHV V8, in 1949.

The factory painted "small-blocks" gold or blue (flat black on the late model 307 cu in (5.0 l)), while "big-blocks" could be red, green, blue, or bronze.

As is the case with all pre-1972 American passenger car engines, published horsepower and torque figures for those years were SAE "Gross," as opposed to 1972 and later SAE Net ratings (which are indicative of what actual production engines produce in their "as installed" state - with all engine accessories, full air cleaner assembly, and full factory exhaust system in-place).

The first generation of Oldsmobile V8s ranged from 1949-1964. Each engine in this generation is quite similar with the same size block and heads.

The 303-cubic-inch (5.0 L) engine had hydraulic lifters, an oversquare bore:stroke ratio, a counterweighted forged crankshaft, aluminum pistons, floating wristpins, and a dual-plane intake manifold. The 303 was produced from 1949-1953. Bore was 3.75 in (95 mm) and stroke was 3.4375 in (87.31 mm). Cadillac used a distantly related engine which appeared in three different sizes through to the 1962 model year; though the Oldsmobile and Cadillac motors were not physically related, many lessons learned by one division were incorporated into the others design, and the result were two engines known for their excellent power-to-weight ratio, fuel economy, and smooth, strong, reliable running.

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