The outbreak of WWII in 1939 brought production of all Series A models to a halt, and when Vincent resumed production at the war's end it was with the all-new Series B. Its rear suspension aside, the Series A Vincent-HRD had been conventional enough: tubular steel frame, girder forks, separate gearbox, etc. but with the Series B Messrs. Vincent and Irving effectively established the marque's reputation for the defiance of convention in the pursuit of engineering excellence. For a start there was no "frame" as such, merely a fabricated box attached to the cylinder heads, which served as the oil tank and incorporated the headstock and the attachment point for the rear springs. The gearbox was integral with the engine, and the swingarm pivoted directly in the engine/gearbox casings, features unusual 60 years ago. Only in the use of the pre-war Brampton girder fork did Vincent appear to be lagging behind others, almost all of which had switched to telescopics, but this shortcoming would soon be addressed by the introduction of the "Girdraulic" fork.

This matching numbers Black Shadow was dispatched from Stevenage on June 5, 1948 to a dealer in California, a V.L. Martin. Why it has a plate from the Grantham & District Motor Cycle Centre, 6 London Road, Grantham – attached to the bike – and a UK registration plate from Lincoln, in Lincolnshire, the next town east from Grantham cannot be explained. It was, however, turned into a most successful drag bike by the original owner and then later had all its original sheet metal put back on it. Somehow it found its way to Brian Burnett's Ferrari of Los Gatos, California - a dealership, which in the 1980s, claimed to sell more Ferraris than any other, and would take in trade pretty much anything - that, in turn, sold it to the current vendor.

The seller, a good friend of the late Big Sid Biberman, last in Louisville, Kentucky, had him carefully refurbish this example. A modern battery and mesh over the carburetor bellmouths were installed, but that apart it remains much as it was when it left the factory. The odometer shows 812 miles, a figure that is thought to be accurate since Big Sid's refurbishment.