The panhead was a Harley-Davidson motorcycle engine, so nicknamed because of the distinct shape of the rocker covers. The engine is a two-cylinder, two-valve-per-cylinder, pushrod V-twin.

In fact, the manufacturer had an entire line of head-themed engines, including the Knucklehead, Panhead, and Shovelhead, with some featuring in the rarest Harley-Davidson motorcycles ever built.

While you may be able to name a dozen prominent American manufacturers, few produce a product as legendary and iconic as Harley-Davidson, Inc. With more than a century of motorcycle building ...