Guy Big J

The Guy Big J was a series of heavy trucks built by Guy Motors of Wolverhampton in the 1960s and 1970s. It was designed around a new, high-revving Cummins V6-200 engine coupled to a 12-speed splitter-type gearbox and was intended for motorway operation. The engine proved unreliable and thirsty, so other makers' units soon replaced it, and AEC, Leyland, Gardner, Cummins and Rolls-Royce engines were all popular choices depending on gross vehicle weight. Gearboxes came from AEC, David Brown and Fuller, and rear axles from ENV or Kirkstall Forge, which allowed so many combinations that the factory recorded every truck on an erection sheet mailed to its dealers. The cab was a distinctive non-tilt design bought from Motor Panels. The success of the Big J range helped keep Guy one of the few profitable companies inside British Leyland until the Fallings Park plant closed in 1982.