MGB 1962–1980: roadster or GT, chrome or rubber bumpers?

The MGB is one of the most common British classics in Europe and one of the easier ones to keep running: simple mechanicals, good parts supply and a large owner community. That does not make every car a good buy — the body decides the value more than anything else. The MB Classics archive includes two MGBs: a 1971 MG MGB roadster, originally delivered to the American market and imported to Poland in 2016, and a 1972 MG MGB GT, built for the Canadian market, in British Racing Green and with an overdrive gearbox.

What is the MGB and how long was it built?

The MGB is MG's two-door sports car, announced in September 1962 and shown to the public at the Earls Court show in October that year. It has a unitary body without a separate chassis. Power came from the 1,798 cc four-cylinder B-Series engine producing 95 bhp at 5,400 rpm (Wikipedia). The brakes are discs at the front and drums at the rear.

Production lasted 18 years, and the last MGB left the Abingdon factory on 23 October 1980 (Classic Car Hub, 2026). Including the MGC and MGB GT V8, 523,836 cars were built. About 9,000 MGBs were also assembled in Australia between 1963 and 1972. Many cars went to the USA and Canada — like both MGBs in our archive — so in continental Europe you often find left-hand-drive cars brought back across the Atlantic.

How does the roadster differ from the MGB GT?

The roadster is an open car with a soft top, while the GT, introduced in October 1965, is a closed coupé with a rear tailgate. The GT roofline was developed with input from Pininfarina. The GT is heavier, but quieter, better protected from the weather and has a practical load area reached through the tailgate.

Two differences matter for a buyer. The first is value: according to Classic Car Hub's April 2026 guide, chrome-bumper GTs are consistently slightly undervalued compared with an equivalent roadster. The second is repair cost. The roadster has no roof to stiffen the body, so it has to be braced during sill replacement to stop the shell from moving; the GT is simpler in this respect (Hagerty UK, 2021).

How did the MGB change over 18 years of production?

The main technical changes in order:

• October 1964 — five-bearing crankshaft instead of three; considered more durable and preferred at high mileages;
• October 1965 — launch of the MGB GT;
• late 1967 (Mk II, 1968 model year) — synchromesh on all four gears, alternator instead of dynamo, negative earth, an optional Borg-Warner 35 automatic (not offered in the USA), dual-circuit brakes on American-market cars;
• 1967–1969 — the MGC with a 2,912 cc six-cylinder engine producing 145 bhp; fewer than 9,000 were built;
• 1973–1976 — the MGB GT V8 with Rover's 3.5-litre engine producing 137 hp; 2,591 built;
• 1974 — plastic bumpers and a higher ride height;
• 1977 — front and rear anti-roll bars, overdrive working on fourth gear only (previously on third and fourth).

The Laycock overdrive is a valued feature — according to Wikipedia fewer than 20% of MGBs had it. The 1972 MGB GT in our archive is one of them. American-market cars are a separate chapter: from 1968 they received emissions equipment, and from 1975 a single Stromberg carburettor instead of twin SUs, which reduced power. The last echo of the model was the 1992–1995 MG RV8 with a 3.9-litre V8 — fewer than 2,000 were built, most of them for Japan.

Chrome or rubber bumpers — which to choose?

Chrome-bumper cars (1962–1974) are more expensive and more sought after, while rubber-bumper cars (1974–1980) are cheaper and usually better equipped. The rubber bumpers were a result of American bumper regulations, and the ride height was raised by about an inch (25 mm) along with them. The result is more body roll in corners; this was only improved by the front and rear anti-roll bars fitted from 1977, which is why the 1977–1980 cars are considered better than the 1975–1976 ones (Hagerty, 2011).

Many rubber-bumper cars have been converted to chrome — conversion kits are easy to get, and the ride height is corrected with lowering blocks. Hagerty UK estimates that a converted car is worth roughly halfway between an original rubber-bumper car and a genuine chrome-bumper Mk III, and that a concours rubber-bumper car loses value through conversion.

Classic Car Hub's April 2026 guide gives indicative UK prices:

These are UK market prices, where right-hand-drive cars dominate. Left-hand-drive cars, common in Poland, usually come from the USA, Canada or continental Europe, and their specification (carburettors, emissions equipment) may differ from British cars.

What are the MGB's weak spots?

The sills come first. On the MGB they are a structural assembly of three parts: the outer sill, the inner sill and the castle rail between them. If you see bubbling where the wings meet the sill, the inner structure is usually in poor condition. A proper replacement costs, according to Hagerty UK, “thousands rather than hundreds” per side, especially on a roadster, which has to be braced during the repair. Classic Car Hub warns that new outer sills fitted over rotten inners are “extremely common”.

Other body areas to check:

• floors — water gets in through the door, windscreen and hood seals; tap the floor with a screwdriver handle;
• front inner wings and suspension turrets and the join with the bulkhead — rust here is expensive;
• rear valance, boot floor (around the spare wheel well and battery tray) and the bottoms of the doors;
• wing top seams and — on the GT — the bottom of the windscreen frame, for which there are no repair sections.

The mechanicals are simple but have their typical faults. A slight leak from the rear crankshaft seal is almost universal; a significant one means removing the gearbox. In the gearbox, check that second gear does not baulk or jump out. Overdrive problems are usually the solenoid or the switch wiring rather than the unit itself. A rear axle whine that rises with road speed points to worn bearings or differential.

What about MGB parts and documentation?

MGB parts supply is exceptionally good. Since 1988 British Motor Heritage has produced complete new MGB bodyshells on the original press tooling and assembly jigs, in batches once enough orders are in — about 60 shells a year (MG Car Club, 2020). This means even a badly corroded car can be rebuilt, but also that when buying it is worth asking whether the car has its original or a new shell. The quality of some replacement parts, particularly rubber items, can be uneven.

The factory specification is confirmed by a Heritage Certificate from the British Motor Museum archive. For MGs from 1953 to 1980 it lists build and despatch dates, engine and body numbers, colours and factory-fitted equipment; a standard certificate costs £52 plus postage (British Motor Museum). This matters because MG did not stamp the paint code on the commission plate until the 1980 model year, and engine swaps are not unknown on the MGC.

If you are interested in other British classics, read the guides to the classic Mini and the Range Rover Classic. The cars I currently have for sale are in the MB Classics stock, and all the guides are in the Models and buyer's guides category.