Sleeper (car)

The American name for this type of vehicle comes from the term sleeper agent[citation needed], whereas the British name is derived from the Q-ships used by the Royal Navy.

[4] In July 1964, British magazine Motorcycle Mechanics carried an announcement from editor Bill Lawless of the use of two unmarked police "Q-cars" — a black Daimler SP250 and a green Austin A40 Farina — patrolling the A20, a road between London and Maidstone.

[6][12] The first Q-car was invented by the Soviet NKVD in 1938,[citation needed] when imported Ford flathead V8 engines were installed in GAZ-M1 cars.

][citation needed] Some vehicle owners create sleepers by swapping more powerful engines,[13] or making other performance modifications, like adding a supercharger or turbocharger, leaving the external appearance as it came from the factory.

Sometimes hints of the car's true nature are visible: wider tires, a lower stance, or a different engine tone or exhaust note.