The final iteration of the P5 appeared in September 1967. Now powered by the
Rover V8 engine also used in the
3500, the car was badged as the "3.5 Litre", and commonly known as the 3½ Litre. The final letter in the "P5B" model name came from
Buick, the engine's originator. Rover did not have the budget to develop a new engine; hence, they chose to develop the lightweight aluminium Buick engine, making it considerably stronger. While this added some weight, it still maintained the engine's light and compact features. The Borg Warner Type-35 automatic transmission,
hydrosteer variable ratio power steering and front Lucas fog lights were now standard. Output of was claimed along with improved torque. The exterior was mostly unchanged, apart from bold "3.5 Litre" badging, a pair of fog lights which were added below the headlights, creating a striking four-light array, and the fitting of chrome
Rostyle wheels with black painted inserts. The P5B existed as both the 4-door coupé and saloon body style until end of production. Production ended in 1973, by when 9,099 coupés and 11,501 saloons had been built. For that reason, registered relatively new-looking P5s were therefore still familiar sights in
Westminster for more than a decade after production had ended. When Margaret Thatcher entered
Downing Street in 1979 after
her election victory, she was driven in a 1972 model. It was during Thatcher's eleven-year tenure that the P5 was eventually phased out as a Prime-Ministerial car, in favour of the
Jaguar XJ.
Queen Elizabeth II also owned an Arden Green Rover P5B Saloon "JGY 280", which is on display at the
Heritage Motor Centre,
Gaydon, Warwickshire and was seen in the 18 May 2003 episode of BBC motoring show
Top Gear. ==Motorsport==