- The first Panhead Harley-Davidson motorcycles debuted in 1948. The design was intended to improve oil flow and consumption over that of the existing Knucklehead engines. The Panheads retained the model designations of the Knuckleheads: E, EL, ES, F, FL and FS -- and bikes were produced with 61- and 74-cubic-inch engines. For this model year, the head covers were chromed, but in subsequent years they would be made of stainless steel.
- One of the first major innovations of the Panhead era was the introduction of hydraulic front forks in 1949. Harley-Davidson called this feature Hydra-Glide and included it on all Panhead models. A spring suspension option remained available on the Sidecar Twin and Sport Solo models; these models were designated EP and ELP for the 61-cubic-inch version and EP and FLP for the 74-cubic-inch version. Another significant development of the early Panhead years was the introduction of a foot shifter.
- In 1958, Harley-Davidson added hydraulic rear suspension to the Hydra-Glide and rechristened the feature Duo-Glide. By this time, the Panhead Sport Solo and Super Sport Solo were available only with 74-cubic-inch engines. The design of the Panhead bikes was continuously tweaked through the first half of the 1960s, with cosmetic changes such as the introduction of an aluminum headlight nacelle in 1960 and mechanical upgrades such as a single-fire ignition system in 1961.
- The reign of the Panhead came to an end in 1965 as the as the first Electra Glides became the last Panhead models. The Electra Glide was so named because it incorporated a 12-volt electric system. The 1966 model saw the transition to the new Shovelhead engines, although these early Shovelheads are sometimes called Pan-Shovels because they retained the distinctive timing covers from the Panhead.