improving its new offering, going down the familiar route, already trodden with the 'flat heads', of increasing engine capacity to 74ci (1,200cc) in the models FS (medium compression) and FL (high compression). Introduced in 1941, the new 'Seventy-Four' incorporated a host of improvements enabling the engine to cope with the increased power, which was now up to 48bhp in the FL's case. By the late 1940s the Knucklehead was beginning to show its age, prompting Harley to engage in a wholesale revision for 1948 in the form of the Panhead. While the engine's bottom end remained fundamentally unchanged, the top end gained aluminium cylinder heads and those distinctive rocker covers. Oil lines were internalised and hydraulic valve lifters adopted, an innovation that greatly reduced tappet noise and simplified maintenance. Maximum power went up to 50bhp in the 74ci FL, but the main advantage of the many improvements was greater reliability. The 'Panhead' featured a new 'wishbone' frame incorporating bowed front downtubes, and in 1949 gained an hydraulically damped telescopic front fork, becoming the 'Hydra-Glide', though this name was originally applied only to the fork and did not become an official model title until 1952. The advent of rear suspension in 1958 saw the Panhead renamed 'Duo-Glide', while with the addition of an electric starter in 1965 it became the 'Electra Glide'.