Premiered in 1919, the engine was successively adopted by subsequent AC models, ending its career under the bonnet of the AC Ace in 1963.

Developed during the First World War by John Weller, one of the brand’s founders, the two-liter block was very advanced for its time, and it remained surprisingly up-to-date even in the 1960s.

The sturdy engine had an aluminum block and its crankshaft was supported by five lubricated sleeve bearings.  The innovative steel cylinder head allowed the engine to be easily adapted for different build and power levels.

With a capacity of 1991cc and two valves per cylinder operated by a single overhead camshaft, the AC engine was fed by a simple carburetor. The original AC Six engine delivered 40hp.

The small AC Six, measuring only 2820mm in wheelbase and weighing a ton, had a separate pressed steel chassis with tubular reinforcements. Both axles were supported by leaf springs with inertia dampers fitted to the front axle, whilst braking was carried out by four drums.

In terms of bodywork, AC Cars offered two- and three-seat Tourer and Saloon models, which included the Ace, Acedes, Aceca, Magma and the Aero among others.

As a way of promoting its cars in the 1920s, the English brand attempted record-breaking runs at the Brooklands track. But it would be a victory for Victor Bruce in the 1926 Monte Carlo Rally that would bring their much-sought fame.

A year earlier, AC Cars would become the first English brand to enter a model in the famous Monegasque rally, and in 1926, the first victory for an English driver and the first for an English brand would be unrestrainedly celebrated.

The car in question was a Six equipped with an original Aceca body in which only the passenger door existed—forcing the driver to cross over the seats to enter the cockpit. In the absence of a door, the right side of the car was equipped with two spare wheels, supported on a platform. In 1927, Victor Bruce’s wife Mildred Bruce would also cross the finish line in sixth place.