Vincent Black Shadow to the new specifications. The prototype Black Shadow had engine number F10AB/1B/558 in frame R2549, and was completed on 16 February 1948. The bike was road tested by Charles Markham in Motor Cycling May 1948, during which test the bike was reported to have reached . The Black Shadow was officially introduced at the 1948 Motorcycle Show at Earls Court in London. 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. Official records say that 1774 Vincent Black Shadows were made. Vincent also built 15
Vincent Black Shadow engine's ports. Early Black Shadows have a third inner valve spring not shared with the Rapide, but this feature was dropped from later bikes. Due to the low-octane 'Pool' petrol that was all that was available in the early post-war years, bikes of the period could have only low compression ratios. Although the prototype Black Shadow was built with a compression ratio lower than the Rapide's nominal 6.8:1, production Shadows have a ratio of 7.3:1 due to having different pistons from the Rapide, although still supplied by Specialloid. The Black Shadows have different carburettors than the Rapides, with Series B