Which automaker introduced the first car with a V16 engine?

The automaker that introduced the first production car with a V16 engine was Cadillac.

Cadillac unveiled its V-16, also called the Series 452, in January 1930. Its 452-cubic-inch overhead-valve engine used sixteen cylinders arranged in two banks, delivering exceptional smoothness and prestige at a time when large multi-cylinder engines symbolized engineering excellence. General Motors designer Harley Earl helped shape the model, while Cadillac developed the engine in secrecy.

The car was extraordinarily expensive and offered a wide range of custom-finished body styles from Fleetwood and Fisher. Cadillac built 4,076 V-16 cars during the model’s 1930–1940 run, with most produced during the first year before the Great Depression sharply reduced luxury-car demand.

A common mix-up involves Marmon. Marmon began developing its own V16 earlier, in 1927, but the Marmon Sixteen was not released until 1931. Cadillac therefore holds the production-car first, even though Marmon’s development work started sooner. The 1930 Cadillac V-16 should also be distinguished from Cadillac’s 2003 Sixteen concept, which never became a production model.