MGB GT V8
Reviewed by Unique Cars and Parts
Our Rating: 4
MG began offering the MGB GT V8 in 1973
utilising the aluminium-block 3528cc Rover V8 engine, first fitted to the Rover P5B
, and subsequently used in the A-body platform Buick Special, Oldsmobile F-85 and Pontiac Tempest. At the time, the sweet spinning engine was the lightest mass-production V8 in the world, with a dry weight of only 144 kg, and was about 27 kg lighter than its 4-cylinder counterpart.
Unfortunately for MG aficionados in the USA
, British Leyland
decided it would be too expensive to make it comply with the innumerable rules it would be faced with before getting into U.S. dealers' showrooms. The American MG
enthusiast was definitely the poorer for it, because with an engine of twice the capacity of the original unit under its hood the MGB GT V8 was infinitely better suited to American driving conditions.
In the UK Ken Costello had been creating tuned versions of a MGB V8 for some time, so it was logical for MG to contract Costello to build them a prototype MGB GT V8. However, the powerful 180 bhp (134 kW) engine used by Costello for his conversions was replaced for production by MG with a more modestly tuned version producing only 137 bhp (102 kW) at 5000 rpm.
The Detoxed V8
This "detoxed" version had its compression ratio lowered to 8.25:1 and an entirely new intake manifold aspirating from twin constant-depression Strombergs located at the rear end of the engine, so that not even a "power bulge" was required to squeeze the V8 under the standard bonnet. Though it had twice the capacity of the four it did not deliver anything like twice its power; but its 102 kW was enough to raise the MG's performance into an altogether different class.
Better still there was no penalty in handling; the alloy V8 was actually lighter than the four, though its heavier ancillaries ended up slightly increasing the weight hidden under the bonnet. Uprated brakes
were also responsible for the slightly higher overall weight of the V8 model. Other modifications were strictly related to the more powerful engine: they included a slight relocation of the rack-and-pinion steering
box and a universal-jointed column to clear the engine, higher intermediate gear ratios, a standard overdrive, and stiffer rear springs
- mainly to prevent axle windup with the increased torque.
The diameter of the front anti-roll bar
was also increased, presumably to maintain the front-to-rear roll-stiffness balance. Wheels with cast alloy centres and steel rims and a heated rear window were standard kit. Apart from that, no attempt was made to otherwise update the basic model, which externally was both good looking and modern but by 1973
it could have done with a better dashboard arrangement and less haphazard controls for the heating and ventilating system.
On The Road
While the bigger engine had most motoring journalists heaping praise, the decision to stick with an overdrive 5th gear was a major disappointment. A proper 5th gear would have been so much better than the electrically controlled overdrive, and would have proved to be more reliable and lighter. Perhaps the location of the electronic overdrive was the problem for many, an overdrive stalk mounted on the steering column and operated with the same hand as the gear lever
was an ergonomic nightmare. Why MG did not place it on the gear-lever knob so that the gear lever
and the overdrive switch could be manipulated simultaneously left everyone wondering.
It was obvious that the V8 version of the MGB would be a much better performer, but who would have thought it capable of achieving a 0-60 mph in 7.7 seconds, 0-100 mph in 23.4 seconds and the standing quarter-mile in 15.8 seconds, and a mean maximum speed of fractionally over 125 mph. Subjectively many claimed the car felt slower than this, probably because the subdued V8 burble made the engine appear lazy, and also because the apparently quite heavy flywheel defeated spectacular fireworks in the lower gears. And as was often the case with a big, lazy engine in a comparatively light car, within certain limits it did not seem to make much difference which gear was selected.
Though the ride was acceptable, when the MG BGT V8 was driven fast on good roads, indifferent country lanes showed up the "vintage" character of the suspension
and the ride became harsh. But when compared with the 4 cylinder MGB, most agreed that both handling and roadholding did not suffer. When the car was released, what was basically a 12-year-old design running on 5-inch-wide rims could not have been expected to offer the ultimate in cornering power, but the handling was balanced and predictable, only slightly biased toward understeer but with plenty of power to hang the tail out as required. These good manners were enhanced by the accurate steering
, which provided good feel and had (at last) exchanged its oversize steering
wheel for a more reasonably sized, soft-rimmed one. Good feel was also provided by the servo-assisted brakes
and heel-and-toeing was easy. Inside the cabin MG introduced pleated brushed nylon front seats, which offered slightly better grip.
Under the bonnet, the V8 engine installation was quite neat and important items were much more accessible than seemed possible, given the shoehorning operation required. Only the plugs were awkward to get at, and the hydraulic tappets made the removal of the cast aluminium valve covers unnecessary. On home soil, the MG BGT V8’s nearest competitors were the 3-litre Capri (nearly equalling its performance) and the Mini Cooper. A tough choice – but one we would have loved the opportunity to have made. Production ended in 1976
MG MGB GT V8 Quick Specifications:
Type - ohv V8, Bore x stroke, mm - 88.9 x 71.1, Displacement, cc/cu in - 3528/215, Compression ratio - 8.25:1, Bhp @ rpm, SAE net - 131 @ 5000 Torque @ rpm, Ib-ft- 185 @ 2900, Fuel requirement - 94-octane.
4-sp manual 4- OD Gear ratios: OD (0.820) - 2.52:1, 4th (1.00) - 3.07:1, 3rd (1.26) - 3.86:1, 2nd (1.97) - 6.06:1, 1st (3.14) -9.63:1, Final drive ratio - 3.0:1.
Chassis and Body:
Body/frame unit steel, Curb weight, lb – 2425. Wheelbase, in - 91.1, Track, front/rear - 49.0/49.2, Length - 154.8, Width - 60.0, Height - 50.0, Fuel capacity, U.S. gal - 14.0.
10.7-in. disc front, 10.0 x 1.7-in. drum rear; vacuum assisted.
alloy centre, steel rim; 14 x 51.
Dunlop radial. 175HR-14.
Rack & pinion, Turns lock-to-lock - 2.9.
front/rear; unequal A-arms, coil springs, lever shocks, anti-roll bar
/live axle, leaf springs, lever shocks.