The Rochester Ramjet is an automotive fuel injection system developed by the Rochester Products Division of General Motors and first offered as a high-performance option on the Corvette and GM passenger cars in 1957. It was discontinued partway through 1965 in favor of the Chevrolet Big Block as a performance option. Unlike electronic fuel injection systems that would become common decades later, the Ramjet is purely mechanical and relies on vacuum and pressure signals to measure airflow and meter fuel.