Cadillac’s first and only production twelve-cylinder model spanned seven years.

The Series 370-A debuted in 1931 to compete against similar offerings from Auburn, Hispano-Suiza, Packard, Pierce-Arrow, Lincoln, and others.

Truly luxurious in every way, Cadillac’s V-12s sat between the standard V-8s and range-topping V-16s, with semi-custom bodies by Fisher and Fleetwood on 140- and 143-inch wheelbases.

The 368 cubic-inch V-12 engine was essentially a truncated version of Cadillac’s overhead-valve V-16.

Output at launch was rated at 135 horsepower—40 horsepower less than the V-16—and would increase to 150 horsepower in 1935.

Cadillac updated subsequent models, designated Series 370-B through 370-E.

Notable changes included introducing a new chassis and other mechanical advancements on the Series 370-D of 1934, while “Turret top” closed-roof Fisher bodies debuted on the Series 370-E the following year.

In 1936, Cadillac renamed its V-12 models the Series 80 and 85, shortening the w...