The Rolls-Royce Silver Cloud is a luxury automobile produced by Rolls-Royce Limited from April 1955 to March 1966. It was the core model of the Rolls-Royce range during that period. The Silver Cloud replaced the Silver Dawn and was, in turn, replaced by the Silver Shadow. The J. P. Blatchley design was a major change from the pre-war models and the highly derivative Silver Dawn. As part of a range rationalisation the Bentley S1 is very similar, apart from its radiator grille. Models Silver Cloud Construction is body-on-frame, which permitted special bodied versions, though the overwhelming majority were built with the standard Pressed Steel Company manufactured steel body shell. A light-weight aluminium alloy was used for doors, bonnet/hood and boot/trunk lid. The chassis is a simple steel box section, welded together and very rigid. The car is long, wide, and weighs 1.95 tonnes. The engine is a 155 hp / 4000 rpm six-cylinder unit with inlet over exhaust valves: twin SU carburettors were added in September 1957. The standard transmission was a four-speed automatic, the General Motors designed Hydramatic transmission. The turning circle was . Brakes are hydraulic and assisted by the Rolls-Royce mechanical servo with drums and suspension was independent coils at the front and semi-elliptic springs at the rear. Twin brake master cylinders were incorporated from April 1956. Power steering and air conditioning became available as options in 1956. A long-wheelbase version lengthened by was also made available in September 1957, outwardly very similar to the existing car but offering improved leg space for rear-seat passengers. The British Motor magazine tested a standard-wheelbase factory-bodied Series I in 1956 recording a top speed of and acceleration from 0- in 13.5 seconds and a fuel consumption of . The test car cost £5078 including taxes. The coachbuilder Harold Radford offered conversions of the 4-door saloon into an estate car. One of these conversions, chassis no. LSMH65, sold in March 2017 for $583,000 (inclusive of applicable buyer's fee) at RM Sotheby's Amelia Island auction. Silver Cloud II The Silver Cloud II was introduced in 1959. It was little changed externally, but was given a new Rolls-Royce developed 6.2 L V8 engine, which pushed the weight to 2.11 tonnes. Performance was greatly improved and top speed was raised to , but the main improvements were in acceleration and torque. Power steering became standard. Electrically operated windows were now available as an option.