The DB4 is a sports car sold by Aston Martin from 1958 until 1963. It was an entirely different car from the DB Mark III it replaced, though the 3.7 L engine was externally visually related to the 2.9 L unit found in that car. The DB4's unique design and performance would later form the basis for future Aston Martin classics, such as the DB4 GT Zagato, the Lagonda Rapide 4-door saloon, and its ultimate replacement the Aston Martin DB5.
The 3.7 L (3670 cc/223 in³) engine, designed by Tadek Marek, was a double overhead cam straight-6, with cylinder head and block of cast R.R.50 aluminium alloy. The engine was prone to overheating initially, but the 240 hp (179 kW) produced by the twin-SU carburettor version made buyers forgive this unfortunate trait. Servo assisted Disc brakes were fitted all around, with early 11.5 in (292 mm) Dunlops being replaced by Girlings. The independent front suspension used ball-jointed wishbones and coil springs and the live rear axle also using coils springs with location by a Watt's linkage. Rack and pinion steering was used. There was a choice of final drive ratios, the normal one for British and European use was 3.54:1, the United States usually got a 3.77:1 and a 3.31:1 was also available for customers wanting a car with an especially high top speed.
A car with the British standard 3.54 final drive ratio tested by The Motor magazine in 1960 had a top speed of 139.3 mph (224.2 km/h) and could accelerate from 0-60 mph (97 km/h) in 9.3 seconds. A fuel consumption of 17.7 miles per imperial gallon (16.0 L/100 km; 14.7 mpg-US) was recorded. The test car cost £3967 including taxes.
