The General Motors Le Sabre was a 1951 concept car (or show car).
The Le Sabre was the brainchild of General Motors Art Department head Harley Earl, by a followup to his famous 1938 Y-job. Like all of Earle's projects, it was built to be roadworthy. It was powered by a supercharged 215 cu in (3.5 L) V8 able to run on gasoline (petrol) or methanol (like Indy roadsters of the period did), and had an unusually-placed rear-mounted Buick Dynaflow automatic transmission. This was later changed to a GM Hydramatic.
The Le Sabre featured numerous advanced features: a 12-volt electrical system (most cars of the period were 6-volt), heated seats, a wrap-around windshield, electric retractable headlights (the 1936-7 Cord 810 had hidden lights, but used vacuum motors), a water sensor to activate the power top, and electric lifting jacks integral to the chassis to aid tire changes. (This idea would be copied decades later by Formula One race teams.)
It was GM's first use of a rear-mounted transmission, which would reappear in the Pontiac Tempest. It was also the first use of the aluminum-block 215, which appeared in the Buick Special and Skylark, Olds Cutlass F-85 and Jetfire, Pontiac Tempest and LeMans, and ultimately in numerous British marques, including Land Rover, Triumph, MG, and Morgan. It was also the first appearance of front bumper dagmars, later made famous on 1957-9 Cadillacs.
It was also GM's first use of the Le Sabre name, which would be adopted by Buick for a new line in 1959.