Many historians assume the MGC was just an MGB with the engine from the Austin-Healey 3000, but it was not that simple. Although the MGC’s inline six had the same bore and stroke as the big Healey, it was essentially a new engine, similar (though not identical) to the one developed for the Austin 3-litre sedan.
The main problem with the earlier C-series, which dated back to 1954, was its prodigious bulk. The big six was a sizable lump of iron weighing about 610 lb (277 kg) — more than a small-block Chevrolet V8. It was also considerably undersquare (the stroke exceeded the bore) and had only four main bearings. Syd Enever pushed for an extensive modernization of the C-series, including different bore and stroke dimensions, but BMC technical director Alec Issigonis overruled him on cost grounds. However, Issigonis did approve the development of a new seven-main-bearing crankshaft. Engineers at BMC’s Coventry Engines Branch also redesigned the engine to reduce its exterior dimensions and take advantage of the latest thinwall casting techniques.
Unfortunately, these efforts were not quite as successful as anticipated. Coventry Engines had hoped to bring the big six’s dry weight under 500 lb (227 kg), but even with all the changes, the engine still weighed a hefty 567 lb (257 kg), 209 lb (95 kg) more than the 1.8-liter (110 cu. in.) B-series four. The redesigned engine was a useful 1.75 inches (45 mm) shorter than its predecessor, but the six remained a tight squeeze for the MGB’s engine bay, especially since budget restrictions prohibited any alterations to the monocoque structure or the firewall. Even after pushing the radiator well forward and adding a deeper U-shaped front crossmember, the MGC’s hood had to be bulged to clear the six’s valve cover and a second, smaller bulge was needed to accommodate the carburetors.
The new crossmember precluded the use of the MGB’s coil springs and lever-action dampers (which also served as the upper control arms), so the MGC got a new front suspension with tubular shock absorbers and torsion bars. A new vacuum-assisted Girling brake system replaced the MGB’s Lockheed brakes and 15-inch wheels with five-lug hubs replaced the B’s four-lug 14-inch wheels. To keep steering effort manageable with the bigger wheels and greater front-end weight, the steering ratio was increased (numerically) by more than 15% while the driveshaft and rear axle were beefed up to withstand the six’s torque. The standard transmission was essentially the new fully synchronized four-speed from the MGB Mk 2, albeit with different ratios. As with the Mk 2 MGB, both Laycock de Normanville overdrive and a three-speed Borg-Warner Model 35 automatic were optional.
All of these changes made the MGC roughly 400 lb (180 kg) heavier than a comparable MGB — and more than 20% more expensive to boot. Inevitably, the six-cylinder car also cost more to run than its four-cylinder sibling. Fuel consumption was around 10% higher and the big six made the MGC a costly proposition in European nations that based vehicle taxes on engine displacement.
THE COLD SHOULDER
Anyone expecting the MGC to be the first MG Supercar was to be sorely disappointed. The first warning sign was that the new six was actually less powerful than the outgoing Austin-Healey 3000 — rated output had fallen from 150 hp (112 kW) to a nominal 145 hp (108 kW). Although the rated torque output (variously quoted at 170 and 174 lb-ft (230 and 235 N-m)) was stout enough, testers soon found that the new head and manifold design had robbed the MGC of the big Healey’s robust low-end urge. Moreover, while the big six was smoother than the MGB’s four, restrictive breathing and a very heavy flywheel kept the new C-series engine from revving with any notable enthusiasm.
The MGC was indeed faster than the MGB: An MGC roadster with manual shift was capable of 0-60 mph (0-97 km/h) in about 10 seconds and a top speed of nearly 120 mph (193 km/h) — not as fast as the last Austin-Healey 3000 or the six-cylinder Triumph TR5 PI, but highly respectable for a British sports car of this era. However, the MGC was neither as quick nor as effortless as its displacement and rated output suggested, and testers felt that it demanded too much effort for too little return.
As dissatisfied as the automotive press may have been with the engine, they reserved the real critical brickbats for the MGC’s handling. The MGC rode better than the B — no bad thing — but its higher center of gravity, inadequate roll control, and greater front weight bias induced substantial understeer, exacerbated on early press cars by improper tire pressures. Reviewers also complained that the slower steering and larger turning radius made the MGC feel cumbersome in low-speed maneuvers, a sensation alien to the MGB. American testers were disappointed while British critics reviled the MGC as something less than a sports car.
(We must qualify those scathing reviews by noting that the early MGB was considered one of the best-handling production cars of its era. Its controls were heavy and the ride sometimes bordered on the abusive, but it had sharp, accurate steering and a pleasing directness that won it many fans. In comparison, the heavier, softer MGC could hardly avoid being seen as a retrograde step.)
Between the higher prices and the dismal notices, buyers shied away. MGC sales were dismal — even in the U.S., which had far fewer barriers to big-engine cars. Worldwide sales for the 1968 model year totaled only about 5,000 units, including both roadsters and GTs. Despite its generally frosty reception, the six-cylinder car did find at least one friend in high places: HRH Charles, Prince of Wales, selected a 1968 MGC GT coupe as his first car. Curiously, BMC’s press office did not really publicize that fact. Their discretion was admirable, but the MGC needed all the help it could get.