For a few years, Buick had the unusual habit of identifying their engines by naming them by their torque output. This engine was the Wildcat 445, which is a 401 CI, of 325 HP. As you might expect, it created some confusion.

This engine was available from 1959 through 1966. To further confuse things, this engine was used in the 65 and 66 Gran Sport, and listed as a 400 CI, to get around GM's ban on engines bigger than 400 CI in intermediate size cars.