How Chevy’s 327 Small Block Earned Its ‘Mighty Mouse’ Nickname: Jalopnik

The Mighty Mouse – not to be confused with another very famous cartoon mouse with the same initials – was an animated hero created by the Terrytoons studio for 20th Century Fox in 1942. Mighty Mouse became popular through his numerous appearances in films and television programs in the following decades. A pocket-sized superhero, the mouse became known for packing a powerful punch into a tiny frame, inspiring the colloquial use of its name to refer to all things small but mighty.

Between 1962 and 1969, Chevrolet produced a new and beloved version of its small-block – the 327-cubic-inch V8 – that was just that: small, but respectably powerful. It weighed 100 pounds less than Chevy’s 348 (a big block), but produced more than 300 horsepower in some configurations. The 327 likely earned the nickname Mighty Mouse as a natural result of both the engine and character achieving cultural popularity in their respective industries for being compact yet powerful. The big blocks of the era similarly earned their “Rat Motor” nickname; mouse is to rat what small block is to big block.

The Chevy 327 “Mighty Mouse” V8 is a small-block engine that was installed in almost every vehicle Chevy produced during that period – from the Impala to the El Camino. The 327 produced respectable power (250 hp, 350 lb-ft of torque in base models). Despite its classification as a small-block engine, it had a stroke of 3.25 inches and a bore of 4 inches, with a displacement of 327 cubic inches. Its cylinder size and rod-to-stroke ratio made it highly compatible with the most common carburetors and pistons of the time, and suitable for high-speed engines. The stroke length was also considered nearly optimal for power generation; longer than its predecessors to generate more power, but not so long that it is inefficient.

The 327 isn’t ultimately one of the most powerful small-block engines Chevrolet ever built (for example, variations of its successors, including the 350 and 400 engines, produced more horsepower in the same era), but the 327 was beloved for its versatility and substantial horsepower potential for its size. In any case, the little block 327 proved that a lot of power could be generated in a modest package, just like the Mighty Mouse.