MGB GT V8 - Buyer's Guide

By: Unique Cars magazine

Date: 23.01.2019

All-alloy Rover V8s were slotted into a range of models including the original MGB GT

1973-1976 MGB GT V8

Many people had something negative to say about the all-alloy, Rover V8, but that belies the fact they were widely used and have, over time, become hugely popular. Discarded by General Motors, they were seen as too small to be taken seriously (although easily enlarged) with finicky SU carbs not the single big downdraft preferred in North America. In places where summers got hot they were renowned for boiling, even with additional radiator capacity.

Those issues were viewed differently in the UK and, the4se, days, there is ample turning knowledge out there to overcome them.

None of that debate Rover V8s from being slotted into a massive range of models from Morgans and TVRs to the original MGB GT V8.

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MG’s intentions for the new car remain unclear even today. Evaluation models were produced in LHD specification but the V8 was never officially sold to US buyers, despite the engine easily meeting emission targets. The cars were never sold officially in Australia either, ensuring that local MGB sales ended in 1973.

The hatchback V8 was ideally positioned to challenge other fixed-roof, hatch-accessible sports cars though, with Triumph’s GT6 and Nissan’s game-changing 240Z obvious targets.

Even with a more robust casting than the original GM block, the Rover V8 remained lighter by almost 20kg than the all-iron MGB four-cylinder. Using low-compression heads restricted output to a very timid 102kW, however it took creative tuners no time at all to be extracting 130-150kW from the 3.5-litre engine.

The four-speed transmission with overdrive was lifted from the outmoded, six-cylinder MGC and wider, steel wheels replaced the wire-spoked rims that were about to be phased out across the MG range.

UK sales began early in 1973 amid massive industrial unrest. Only months away as well was news that a Middle Eastern oil embargo would affect supply and increase petrol prices by 400 per cent.

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The GT V8 being a light and relatively high-geared car – claimed top speed was over 190km/h – it didn’t fare badly in fuel consumption comparisons. However it did have eight cylinders under the bonnet and this wasn't necessarily a selling point in the British market of the time. During almost three years in production and with sales restricted almost exclusively to the UK, just 2591 were sold.

The vast majority of locally-available B V8s will have spent their early years on British roads. Some may have come here via Japan or other parts of Asia but they all need close examination for rust.

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Standard front seat trim is vinyl with the rudimentary rear bench in cheap fabric folded under the luggage platform. The rear comes with no seat belts and seemingly no provision for their installation.

It is possible to retro-fit air-conditioning but the procedure and additional components needed aren’t cheap. One solution is the fold-back Webasto vinyl sunroof but they can deteriorate and leak.

People rarely buy MGs with the intention of using them as regular transport. However after a few modifications such as a larger-capacity radiator and electric thermo-fan, tackling traffic from behind the wheel of a B isn’t a silly idea.

2019 MARKET REVIEW

It's possible to buy a decent GT V8  for less than $35,000 and some owners opt for a complete,  high-quality restoration using all new parts that will generate a bill of $80,000 or more. Capitalisation to that level won't be recovered in the short term and maybe never.

2019 VALUE RANGE: MGB GT V8

Fair: $15,000
Good: $35,000
Excellent: $50,000
(Note: concours cars will demand more)

BUYER'S CHECKLIST

Body & chassis

Rust attacks the floors, sills, lower mudguards and behind the headlights . Once it gets to the fire-wall and Macpherson strut towers the bills can become uneconomic. Replacement panels and structural steel are available from UK suppliers and local specialists. Water does find its way into MGBs. Local suppliers will also have in stock body rubbers, some glass, chrome and rust repair panels. Decent bumpers, grilles and early tail-lights can be difficult to find and new bumpers at $1000 each are relatively expensive. Complete rear lights are relatively cheap at $85 each.

Engine & transmission

Be wary of exhaust smoke from engines that haven’t been run in a while. They may have cracked or sticking piston rings which can cause further damage if the engine gets hot. Overheating can be cured in most instances by chemically cleaning the radiator and spending $100 on a new water pump. Everything needed for a complete engine rebuild is still available from local suppliers and parts are relatively cheap. The twin SU carburettors often need a rebuild and that runs into money. The gearshift can be sloppy due to worn linkages so make sure gears engage easily. Clutch shudder is usually a symptom of component wear but look also for tired engine mounts.

Suspension & brakes

Basic components and design backed by cheap and easily found parts mean no excuses for an MG with worn and dangerous chassis components. Clunking from the front end and wandering in a straight line suggests worn king-pins and bushes. Bouncing after hitting a bump pretty much guarantees the shock absorbers are shot. King-pin kits cost under $200 with pairs of replacement coil springs at similar money and kits of quality bushings at $150-180 per set. The rear leaf springs can crack or move in their shackles, even allowing the axle to move laterally when cornering. Spring sets can be rebuilt by specialists. The V8’s brakes are a basic disc front/drum rear system and can be upgraded.

Interior & electrics

Just because these cars have an American-designed engine doesn’t immunise them against the electrical gremlins that afflict four-cylinder MGs and other British cars. From the outset make sure everything in the cabin works and if you can, that the headlights shine with equal intensity. Absolutely everything needed to perform a complete overhaul is available, as are correct trim materials.  Flat, ripped seats are common fare in older MGs but complete kits of foam cushions, covers, carpet and console covering cost $2500 plus shipping from the UK.

1973-1976 MGB GT V8 specs

NUMBER BUILT: 2512
BODY: all-steel two-door coupe
ENGINE: 3528cc V8 with overhead valves and twin sidedraft carburettors
POWER & TORQUE: 102kW @ 5000rpm 262Nm @ 2900rpm
PERFORMANCE:
0-96km/h 8.7  seconds
0-400 metres 16.0 seconds
TRANSMISSION: Four-speed manual, three-speed automatic
SUSPENSION: Independent with coil springs, A arms. lever-action shock absorbers (f)  live axle with semi-elliptic springs and lever-action shock absorbers
BRAKES: disc (f) drum (r) some with power assistance
TYRES: 175HR14 radial

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