What was Harley-Davidson’s first overhead-valve production V-twin called?

Harley-Davidson’s first overhead-valve production V-twin was called the Knucklehead.

Introduced in 1936, the Knucklehead represented a major technical step beyond Harley-Davidson’s earlier side-valve engines. Its overhead-valve layout allowed improved breathing and helped support stronger performance. The engine’s characteristic rocker boxes created the visual “knuckle” shape that produced its widely used nickname.

Harley-Davidson had already built V-twin motorcycles before 1936, but not every earlier V-twin used overhead valves. The distinction matters because “V-twin” describes cylinder arrangement, while “overhead valve” describes the valve-train design. A flathead, for example, can be a V-twin without being an overhead-valve engine.

The Knucklehead’s successors were the Panhead in 1948 and the Shovelhead in 1966. These names are often used as shorthand for different eras of Harley-Davidson big-twin engineering and styling.