The cars were also marketed in Denmark as the Wolseley 300.
There were two other Farina-designed car lines launched by BMC at the same time — the compact Austin A40 Farina and midsized Wolseley 15/60 and derivatives. Although similar-looking, the latter shares no body parts and few other parts with the big Wolseley.
The first generation of the large Farinas was introduced with the Austin A99 Westminster, with the Wolseley 6/99 following shortly after in 1959 to replace the 6/90. It used the same 2.9 L (2912 cc) C-Series straight-6, 102 bhp (76 kW), twin SU carburettor engine from the Austin-Healey 3000.
The suspension was the conventional BMC arrangement of coil springs and wishbones at the front with a live axle and semi elliptic leaf springs at the rear. An anti-roll bar was fitted at the front. Lockheed 10.75 in (273 mm) discs brakes were fitted at the front with 10 in (250 mm) drums at the rear and vacuum servo assistance.
The interior was finished in luxurious style to distance the Wolseley from its Austin stable mate. The dashboard was polished wood as were the door cappings. Leather upholstery was used on the two front seats and rear bench seat which had a fold down central arm rest. A choice of single or duo tone colour schemes was offered.
The Motor magazine tested a 6/99 with overdrive in 1959 and recorded a top speed of 97.6 mph (157.1 km/h) and acceleration from 0-60 mph (97 km/h) in 14.4 seconds. A "touring" fuel consumption of 23.6 miles per gallon(imperial) was recorded. On the home market, as tested with overdrive, it cost £1254 including taxes of £369.
The large Farinas were updated in 1961 as the Austin A110 Westminster and Vanden Plas Princess 3-Litre Mk. II. It used the same engine but now tuned to give 120 bhp (89 kW). The gear lever moved to the floor from the steering column. Hydrosteer variable ratio power steering and air conditioning were options from July 1962. Wolseley 6/99s with left hand drive shipped to Canada used the 4-speed floor mounted shift with overdrive identical to that in the Austin-Healey 100/6 and 3000.
A Mark II model was released in 1964 with smaller (13 in) wheels and a 4-speed transmission, overdrive was still available but now an option. Production of the Mark II ended in March 1968. Only the Austin was replaced directly, with the unsuccessful Austin 3-litre, which remained in production until 1971. Luxurious Wolseley and Vanden Plas versions of the 3-litre both reached prototype stage, but went no further.