The Bentley Mark VI is an automobile from Bentley which was produced from 1946 to 1952. The Mark VI 4-door standard steel sports saloon was the first post-war luxury car from Bentley. Announced in May 1946 and produced from 1946 to 1952 it was also both the first car from Rolls-Royce with all-steel coachwork and the first complete car assembled and finished at their factory. These very expensive cars were a genuine success, long-term their weakness lay in the inferior steels forced on them by government's post-war controls. Chassis continued to be supplied to independent coachbuilders. The Mark VI 4 1⁄4-litre used an F-head straight-6 engine 4.3 L (4,257 cc/259 cu in) in size. The manufacturer refused to disclose a horse power value for the car (other than Tax Horsepower of 29.4 hp according to the old RAC formula) but an Autocar Magazine road test reproduced in 1950 reported that top gear provided "flexibility down to 6 mph (10 km/h)" and the ability to "climb a hill of 1 in 9 maximum gradient, complicated by bends", all of which supported the manufacturer's contention that power, along with low speed torque, were adequate.