The bus chassis variant of the International S series is a cowled bus chassis that was produced by International Harvester from 1979 to 2004. Produced primarily for school bus applications, the chassis was also produced for other applications, including commercial-use buses and cutaway-cab buses. In addition, the cowled chassis formed the basis for front-engine and rear-engine stripped chassis produced for bus applications.

The International 3300 is a Type-C cowled bus chassis (conventional-style) manufactured by Navistar International, derived from the International DuraStar since 2004 for the United States, Canada, and Mexico. While most examples are produced as yellow school buses, variants of the 3300 are also produced for commercial applications; International also produces as cutaway-cab variant of the model line.