Since 1955, the Chevrolet Corvette has been powered by the Chevrolet V8 engine. Technological advancements have increased output from 195 hp in 1955 to 638 hp in 2012, but the fundamental architecture of the Chevrolet Small Block have remained the same; a 90-degree V8, with overhead valves actuated by pushrods, and a 4.4-inch on-center bore spacing.
From 1929 and 1955, Chevrolet only offered six-cylinder engines. To address the burgeoning performance market, chief engineer Ed Cole set out to design a Chevrolet V8 that was powerful, lightweight and affordable. His solution was elegantly simple: a compact, efficient 90-degree V8 engine, featuring overhead valves, pushrod valvetrain, and 4.4-inch on-center bore spacing. The Chevrolet Big Block follows the same formula, with the exception of a wider 4.8 inch bore spacing.