Q-car

A sleeper (US English) or Q-car (British English) is a car that has high performance and an unassuming exterior. Sleeper cars are so called because their exterior looks little or no different from a standard or economy-class car. In some cases the car appears worse due to seeming neglect on the owner's part, typically referred to as "all go and no show". While appearing to be a standard or neglected car, internally they are modified to perform at higher performance levels. The American nomenclature comes from the term sleeper agent, while the British term derives from the Q-ships used by the Royal Navy.

In the February 1963 Motor Sport magazine editor Bill Boddy said "the modifications carried out by Lotus have turned [the Lotus Cortina] into a 'Q' car par excellence". In the British film The Long Arm (film) (1956; aka The Third Key) there are mentions of a Q car (unmarked) patrolling the city by night, indicating that the term was in use among UK law enforcement at least a decade earlier.

In July 1964, British magazine Motorcycle Mechanics carried an announcement from editor Bill Lawless of the use of two police 'Q–cars' – a black Daimler SP250 sports car and a green Farina Austin A40 – patrolling the A20 between London and Maidstone, Kent.

The Chrysler 300 letter series began in 1955 with the Chrysler C-300. With a 331 in³ (5.4 L) FirePower V8, the engine was the first in a production passenger car to be rated at 300 hp (220 kW), and was by a comfortable margin the most powerful in American cars of the time. By 1957, with the 300C, power was up to 375 hp (280 kW). These cars were among the first sleepers, marketed as high-end luxury cars from the traditional luxury marque Chrysler, but with a high-end homologation racing engine. However, these cars lose their "sleeper value" due to both their rarity (this series was highly luxurious; it was made in limited numbers and examples are very expensive), and the well publicized successes of Carl Kiekhaefer in NASCAR racing (1955–1956); though the model is an important precursor of the muscle car.

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