This is the year that the first "Hemi," or an internal combustion engine with hemispherical-head chamber design, was introduced. The V8s, then known as FirePower engines, were 331 cubic inches and produced 180 horsepower, an extremely efficient displacement-to-horsepower ratio. The overhead-valve blocks were first used in the New Yorker and the Imperial. The New Yorker, at the time, was Chrysler's top-of-the-line model and was even selected as the Indy 500 pace car that year.