Which car manufacturer produced the first car with a V16 engine?

Cadillac produced the first production car with a V16 engine.

The Cadillac V-16 debuted in January 1930 as the Series 452, an ultra-luxury automobile powered by a 452-cubic-inch overhead-valve V16. It was unveiled at the New York Automobile Show on January 4, 1930, and quickly became Cadillac’s flagship model.

The engine used two banks of eight cylinders arranged at a 45-degree angle. Its smoothness, refinement and imposing specification helped Cadillac compete at the top of the luxury market. Buyers could order the chassis with highly customized bodies from Fisher and Fleetwood.

Marmon is the most common source of confusion. Marmon began developing a V16 engine in 1927, before Cadillac, but its production Marmon Sixteen was not released until 1931. Thus, Marmon began development first, while Cadillac was first to put a V16 into a production car. Cadillac built 4,076 V-16s through 1940.