During World War I they made the ABC designed Wasp and Dragonfly models of aircraft Radial type engine, Tylor truck engines and Maudslay Motor Company gearboxes as well as being the country's largest maker of "Depth charge" fuses. They were bought out by Jaguar in 1961 and badged Guy buses ceased production in 1964. By then the company had developed a completely new range of trucks: the Guy Big J models. The Big J was designed around a new Cummins V6 engine, and was intended for motorway operation. In 1966 Jaguar became part of the British Motor Holdings. Guy Motors' factory was closed in 1982.