THE V8 MGB
In the fall of 1967, MG introduced the MGC, a six-cylinder version of the MGB, powered by the 2,912 cc (178 cu. in.) engine from the Austin 3-litre sedan. While this sounded good on paper, the big six played hob with the B’s weight distribution and handling and the motoring press had promptly beaten the C about the ears. Sales were poor and the MGC was withdrawn in 1969.
The 1968 merger between BMC and the Leyland Motor Corporation had many unfortunate ramifications for MG, but it also presented an intriguing opportunity for a different big-engine B. In 1967, Leyland had acquired Rover, which had recently begun manufacturing its own version of Buick’s old all-aluminum V8 for use in the P5 and P6 sedans. The lightweight, compact 3,528 cc (215 cu. in.) engine soon had the British aftermarket salivating and led the press to speculate whether British Leyland would install the V8 in the MGB. Despite its greater displacement, the Rover V8 was only a few pounds heavier than the B-series four and seemed like a much better match for the MGB’s chassis than did the bulky C-series six.
(Some sources assert that the Rover engine actually weighed less than the B-series, which had a dry weight of about 360 lb (163 kg). While Buick quoted a dry weight of 318 lb (144 kg) for its original 215 cu. in. (3,528 cc) V8, both the Oldsmobile and Rover versions had many minor design variations and were somewhat heavier than the early Buick engine. Dutch Rover enthusiast Rene Winters cites a dry weight of 375 lb (170 kg) for the Rover engine, which would make it 17 lb (8 kg) heavier than the B-series four — still a very modest penalty given the V8’s substantially greater displacement and power.)
At first, British Leyland had no such intention. The fact that Triumph was about to introduce its own V8 sports car, the Stag — powered not by the Rover engine, but by a new 2,997 cc (183 cu. in.) SOHC V8 — may have had something to do with that; a 3.5-liter MGB would have been a direct competitor. According to Robin Weatherall, Austin-Morris engineering director Charles Griffin did explore the possibility of installing the Rover engine in the MGB, but declared in November 1970 that it would be impossible without substantially widening the engine bay.
Around the same time, Abingdon proposed an entirely different V8 MGB using the aluminum Daimler V8, either the 2,548 cc (153 cu. in.) version from the Daimler SP250 sports car or the 4,561 cc (278 cu. in.) engine from the big Daimler Majestic Major. Mock-ups were built to see if the Daimler engine would fit, but it appears that this combination was never seriously considered for production.
Griffin didn’t realize at the time that not only was it possible to install the Rover engine in the MGB, the aftermarket had already done it. In 1969, racing driver Ken Costello had installed the Oldsmobile version of the 3.5-liter engine (from the original Oldsmobile F-85/Cutlass) in a borrowed MGB roadster with promising results. Before long, Costello was building similar cars for friends. He soon formed his own company in Kent, the V8 Conversion Company, offering Rover V8 conversions for customers’ MGB coupes and roadsters. It was an expensive swap, at around £1,000 (about $2,400), but it provided impressive performance with little sacrifice of the stock MGB’s balance and handling.
The Costello conversions received enthusiastic reviews in the motoring press, which in turn came to the attention of British Leyland. In May 1971, Costello received a letter from Charles Griffin inviting him to Longbridge to demonstrate his conversion to Griffin and technical director Harry Webster. Two weeks after that, Costello was summoned to a meeting with chairman Donald Stokes (now Lord Stokes), who commissioned Costello to build a prototype for a production MGB V8, providing a new GT coupe and Rover engine for that purpose.
The production V8, known internally as ADO75, was a more elaborate conversion than Costello’s engine swap, utilizing some of the beefier drivetrain components developed for the defunct MGC. The compact Rover engine didn’t require the MGC’s altered front suspension, although the front crossmember was modified to ensure proper ground clearance, the radiator was moved forward, and the firewall was reshaped to accommodate the V8 bell housing. Rather than using the high-compression V8 from the Rover 3500, Abingdon opted for the mildly tuned Range Rover engine, which still had ample power and was more readily available. (It also put less of a strain on the gearbox, whose torque capacity was sorely tested by the bigger engine.)
The V8 made the ADO75 the fastest stock MGB to date. While the Rover engine was at least nominally less powerful than the old MGC — 137 hp DIN (101 kW) to the MGC’s 145 net horsepower (108 kW) — the V8’s power-to-weight ratio was decisively better. MG advertising claimed a top speed of 124 mph (200 km/h) and 0-60 mph (0-97 km/h) in 8.3 seconds, which was certainly conservative. Since weight and weight distribution were similar to the four-cylinder MGB’s, the V8’s steering, handling, and braking were little changed, but the MGB now had the muscle to face rivals like the Datsun 240Z, Reliant Scimitar GTE, and Ford Capri 3000. Furthermore, the tuning potential of the Rover engine was well known.
Abingdon announced the new model, prosaically dubbed MGB GT V8, in August 1973. With a starting price of £2,085.42 with tax (around $5,000 at the contemporary exchange rate), it cost almost 50% more than a four-cylinder MGB roadster. The V8 was still cheaper than a UK-market 240Z, which was subject to heavy import duties, but an uncomfortable £430 (over $1,000) more than the Ford Capri 3000GT, which had similar performance in a more modern package. The V8 also had the misfortune to bow just before the 1973 OPEC oil embargo, which made buyers shy away from powerful, thirsty cars.
The V8 would probably have done better in the U.S. even after the embargo; by the standards of the American market, it was practically an economy car. British Leyland showed the MGB GT V8 to its North American distributors and Abingdon did build a small number of LHD cars — between six and nine — for evaluation, but the company ultimately elected not to export the V8.
The reasons for that decision are not entirely clear. The cost of federalization was likely a factor; the Rover 3500 had already been withdrawn from the U.S. market, with the Range Rover slated for withdrawal in 1974, and the projected volume of the MGB V8 probably would not have justified the cost of emissions certification (although it was crash tested). British Leyland management may also have wanted to protect the upcoming Triumph TR7 — BL withdrew the four-cylinder MGB GT from the U.S. market in early 1975 for much the same reason.
There have long been rumors — repeated by John Thornley, among others — that Rover’s licensing agreement with GM limited Rover’s total production of the V8, presumably to prevent Rover from competing with GM’s own products. However, Dan Wall, Rover’s head of V8 engine development in the seventies, later told David Knowles that Wall knew of no such restrictions. He said GM executives had long since lost interest in the aluminum engine, which Buick had dropped in 1963, and were more bemused than threatened by Rover’s continued interest in it. Nonetheless, there were limits to Rover’s engine production capacity, most of which was already earmarked for Rover’s own products, including the P6, the Range Rover, and the forthcoming SD1.
Whatever the rationale, the lack of exports sharply curtailed the V8’s sales potential. With no LHD version, the MGB GT V8 couldn’t be sold in Europe (where the market would probably have been limited in any event) and it was too expensive for most Britons, particularly during the fuel crisis. MG continued to offer the MGB GT V8 through the 1977 model year, but sales never topped 800 a year. When production ended in July 1976, the grand total came to only 2,591 cars, making it one of the rarest factory MGBs. Ken Costello, meanwhile, did about 225 conversions in the seventies and another batch in the late eighties.