Description The Rover P5 series (commonly called 3-Litre and 3½ Litre for the engine displacement) was a group of large (in European terms) saloon and coupé automobiles produced from 1958 until 1973. Sometimes called 'the poor man's Rolls-Royce', the Rover P5 was extremely popular with United Kingdom Prime Ministers and government officials of its day and served as Prime Ministerial transport for Harold Wilson, Edward Heath, James Callaghan and Margaret Thatcher.. Even the Queen is said to have favoured driving her Rover P5. The P5B first appeared in 1967. The Rover P5B was powered by a 3.5 litre Rover V8 engine. This V8 engine output 160 bhp.