Kenworth » K series 500 / K series 900 / later - K100

In 1957, the model CSE, which was produced not so long, was replaced by a new model with COE design (cab-over-engine). The model was improved by the introduction of tilt cab which facilitated access to the engine. Trucks with cab over the engine were designed to operate on West Coast, where were strict limits for the length of combinations. This model originally was produced on the basis of a bonneted 500 series, and had a letter '"K" ahead of the index. In 1958, the trucks received twin headlights, instead of the single.

In 1961 cabover trucks started to be produced on a conventional trucks chassis 900 series. The cabover models were known as K900 from that moment. The range included models K921, K923, and K925. Later with the introduction of the W900 series, the cabover range was renamed to K100, and then in 1965 upgraded to a model K100A. Early models had a different design of the front end with single or double rectangular headlights and grille, which remained unmoved while tilting of the cab, because it was rigidly mounted on the radiator. In 1964-1965 a transitional version was produced with the grille from K100A, but the design of the front end similar to old models. K900 were also produced by the Canadian division of Kenworth.