The MG MGB was manufactured from 1962 through 1980 by the British Motor Corporation (BMC) and later as the Austin-Morris division of British Leyland. Development had begun in the late 1950s with a prototype known as the MG EX205. While the MGA and MG T-Types had been built using the traditional body-on-frame construction, the MGB used a modern unitary (monocoque) structure, although many of the mechanical components, including the brakes and suspensions, were developments of the previous MGA. The origins of the B-Series engine dated back to 1947. It was a three-bearing unit (later upgraded to a five-bearing crankshaft in October of 1964) fitted with twin 1.5-inch SU carburetors (albeit, U.S. spec cars built from 1975 onwards had a single Stromberg 1.75-inch carburetor) and paired with a four-speed manual gearbox with a non-synchromesh, straight-cut first gear (from 1962 to 1967). An optional overdrive was available. A full synchromesh unit based on the MGC gearbox became available in 1968, and since it was designed to cope with the 150 (net) horsepower from the three-liter MGC engine, was essentially 'over engineered' for the B-Series engine powering the MGB.
The MGB was an innovative vehicle wearing a modern design and its monocoque construction meant it had lightweight qualities, increased structural rigidity, and reduced manufacturing costs. Standard equipment included wind-up windows, a comfortable driver's compartment, and plenty of legroom. A parcel shelf was fitted behind the seats.
The majority of MGBs were exported to the United States.
Compared to the outgoing MGA, the MGB was three inches shorter but offered more passenger and luggage accommodation. It was a two-seater roadster that was available, at one point, with a small rear seat. The suspension was softer than its predecessors and the larger powerplant meant it had a slightly higher top speed. The MGA rested on 15-inch wheels and the MGB had 14-inch wheels.
Several significant modifications and upgrades arrived in 1968, prompting the Mark II model. Among the changes were the synchromesh transmission on all four cars with revised ratios, an optional Borg-Warner 35 automatic gearbox (except in the United States), the dynamo replaced by an alternator with a change to a negative earth system, and a new rear axle.
New safety and emissions regulations were introduced in the United States during the late 1960s as Detroit continued to introduce larger and more potent powerplants. Coupled with increases in insurance premiums and the oil crisis in the 1970s, the automotive landscape changed significantly during this era. Manufacturers were forced to introduce new updates to their models annually to cope with all these new regulations. In regards to the MGB, the 1968 models received dual circuit brakes and the 'Abingdon pillow' - a plastic and foam rubber-covered 'safety' dashboard. The 'other market' cars continued to be built with a steel dashboard.
In 1969, reclining seats became standard and new Rubery Owen RoStyle wheels replaced the previous pressed steel versions. An additional windshield wiper was added to U.S.-destined cars, now counting three, in compliance with regulations that dictated a percent of the glass should be cleared.
The 1970 MGB gained a new recessed grille in black aluminum, although the polished grille returned in 1973 with a black 'honeycomb' insert. The 1970 MGB also had a one-year-only split rear bumper with the number-plate in between. The following year, the previous single-piece full-length style chrome bumper returned and would remain in use through 1974.
1972 MGB
Changes for the 1972 MBW were mostly found on the vehicle's interior. There was a new center console and armrests, an updated instrument panel with a locking glove box. Pricing began at $3,320 for the roadster and rose to $3600 for the GT Coupe.
Powering the MGB was an overhead-valve four-cylinder engine that displaced 109.8 cubic inches and produced nearly 80 horsepower. There was a four-speed manual all-synchromesh gearbox with a 3.91:1 gear ratio. Disc brakes were in the front with drums in the rear. Three new color options became available, consisting of aqua, dark green and gold.
The GT Coupe 2+2 models had leather inserts.
For 1973, MG sold around 31,991 vehicles in the United States, roughly 400 more than the prior year.
by Dan Vaughan