1964 MGB MKI Roadster: green version
The MGB is a two-door sports car manufactured and marketed from 1962 until 1980 by the British Motor Corporation (BMC), later the Austin-Morris division of British Leyland, as a four-cylinder, soft-top sports car. It was announced and its details first published on 19 September 1962. Variants include the MGB GT three-door 2+2 coupé (1965–1980), the six-cylinder sports car and coupé MGC (1967–69), and the eight-cylinder 2+2 coupé, the MGB GT V8 (1973–76).
Replacing the MGA in 1962, production of the MGB and its variants continued until 1980. Sales for the MGB, MGC and MGB GT V8 combined totaled 523,836 cars. After a 12-year hiatus, the MGB re-entered production as the heavily modified MG RV8 with a limited run of 2,000 cars before finally being replaced in 1995 by the MG F.
The roadster was the first of the MGB range to be produced. The body was a pure two-seater; a small rear seat was a rare option at one point. By making better use of space the MGB was able to offer more passenger and luggage accommodation than the earlier MGA while being 3 in (76 mm) shorter overall. The suspension was also softer, giving a smoother ride, and the larger engine gave a slightly higher top speed. The four-speed gearbox was an uprated version of the one used in the MGA with an optional (electrically activated) overdrive transmission. Wheel diameter dropped from 15 to 14 inches (360 mm).
In late 1967, sufficient changes were introduced for the factory to define a Mark II model for the 1968 model year. Changes included synchromesh on all four gears with revised ratios, an optional Borg-Warner 35 automatic gearbox (except in the US), a new rear axle, and an alternator in place of the dynamo with a change to a negative earth system. To accommodate the new gearboxes there were significant changes to the sheet metal in the floorpan, and a new flat-topped transmission tunnel.