Motorcycles produced by Vincent H·R·D at their factory in Stevenage, Hertfordshire, England were renowned for their design innovation, engineering excellence and high performance.

Each cylinder's two overhead valves are operated through rocker arms and short pushrods by two gear-driven cams mounted high in the engine's timing case.

[1]: 62  The engine's signature colour was achieved by applying a "pyluminising" coating of chromate anti-corrosion primer over which a layer of Pinchin & Johnson black enamel was added.

[2]: 58  Although some have claimed that the black finish increased the rate of heat rejection from the engine, its main real benefit seems to have been its visual impact.

The ratio of the bottom gear was raised from 9:1 to 7.2:1 [2]: 60 As in the Series B Rapide, the engine is mounted as a stressed member, eliminating the need for a downtube cradle.

Series B and C Black Shadows use an upper frame member (UFM) consisting of a fabricated steel box that doubles as an oil tank.

The rear suspension of the Black Shadow is a cantilever system, with a rear frame member (RFM) of two parallel upright triangular members pivoting from heavy plates on the back of the transmission case at the bottom and attached at the top to two spring boxes angled out from the seat post and damped by a hydraulic damper.

[2]: 61  In Series C and later Black Shadows the Brampton unit is replaced by Vincent's own Girdraulic blade-type girder variation that used a hydraulic damper in place of a coil spring.

While the Series B Rapide was not designed to be a racer, PCV felt that steady improvement was necessary and drew up a specification for a version with greater performance.

[1]: 60  Engineer Phil Irving and racer and Development shop head George Brown quietly built two bikes to the new specifications.

So far as the standards of engine performance, handling and braking are concerned – the chief features which can make or mar an otherwise excellent mount – the mighty Black Shadow must be awarded 99 out of 100 marks: 99 because nothing, it is said, is perfect.

[8] The Black Shadows were built with the same labour-intensive hand-fitting of bearings and major engine parts that Vincent had used prior to the war.

[13] In 2007 the Vincent H·R·D Owners Club commissioned the VOC Spares Company Limited to build a replica Black Shadow from new parts.

Having received glowing reviews from the motorcycle press in the UK, the machine was auctioned by Bonhams and eventually went on display at a museum in New Zealand.

[15][16] Journalist Hunter S. Thompson wrote "If you rode the Black Shadow at top speed for any length of time, you would almost certainly die.

The goal was to take the AMA National Class A flying-mile record then held by Joe Petrali and his modified Harley-Davidson and which stood at 136.183 mph (219.165 km/h).

[2]: 88 Vincent mechanic Cliff Brown writes that he built a modified engine for the bike, with extensive porting and polishing and a compression ratio of 12.75:1.

Free then stripped off his racing leathers and on his final run, lying prone on the fender of the bike, set a record speed of 150.313 mph (241.905 km/h).

[citation needed] The four Black Shadows were two pairs of consecutively numbered machines, transported to Montlhery from the Stevenage factory on a Lorry.

[citation needed] Gunga Din was also used for the high speed record attempts in addition to the Black Lightning.