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.

Harley-Davidson's early 1950s shift from Knucklehead to Panhead engines captured the post-war motorcycle culture. The new 2024 Hydra-Glide Revival is a modern interpretation of the classic Panhead ...