Armstrong Siddeley Sapphire 346

Production	1953–1958 7,697 made
Body style	FR layout 4-door saloon limousine
Engine	3,435 cc Straight-6
Wheelbase	114 in (2,896 mm) 133 inches (3,378 mm) (limousine)
Length	193 in (4,902 mm) 212 in (5,385 mm) (limousine)
Width	72 in (1,829 mm)
Height	63 in (1,600 mm)

InThe 346 was the first of the Sapphires introduced late in 1952 for sale in 1953 and continuing until 1958. The six-cylinder 3,435 cc engine had hemi-spherical combustion chambers and could have optional twin Stromberg carburettors (£25 extra) which increased the output from 125 to 150 bhp (93 to 112 kW) giving a top speed in excess of 100 mph (161 km/h). The front suspension was independent coil springs with a rigid axle and leaf springs at the rear. The Girling hydraulic brakes used 11 in (279 mm) drums all round.

The body was available as a four- or six-light (two or three windows on each side) at the same cost and with either a bench or individual front seats. The seats were finished in leather, with the dashboard and door-cappings in walnut veneer. A heater was standard.

It was introduced with the choice of a Wilson electrically-controlled finger-tip four-speed pre-selector gearbox as a £30 option, or four-speed synchromesh gearbox. It became available with automatic transmission (Rolls Royce four-speed) with the introduction of the Mark II in 1954.

A long-wheelbase model was launched in 1955 as a limousine version which had the pre-selector gearbox as standard, however, there was an optional four-speed manual column-change gearbox available.

1958 Armstrong Siddeley Sapphire 346 limousine

Models for export to the U.S. were always delivered with twin caburettors. A twin-carburettor induction system has therefore been developed for export models which increases the maximum power output from 120 b.h.p. to over 150 b.h.p. This system, which has been fitted as standard to all cars shipped to the United States—as have also white-walled tyres and blinking direction indicators has more effect on top gear acceleration than on maximum speed.

The twin-carburettor induction system incorporating two Stromberg downdraught carburettors type DAA 36 is available in the home market as an optional extra, as also
are twin bucket seats at the front instead of the standard bench-type seat. These are also the result of overseas demand. 

• Performance twin-carburettor engine
• top speed of 100.1 mph (161.1 km/h) 
• acceleration from 0–60 mph (97 km/h) in 13.0 seconds
• fuel consumption of 18.7 miles per imperial gallon (15.1 L/100 km; 15.6 mpg_-US)

In total 7,697 were produced up to 1958.