Buyers Guide MGC/’B V8

Buyers Guide MGC/’B V8

Seven steps to buying an MGC and ’B GT V8 Sporting appeal with the thrust to match the looks for as little as £6500. Words Richard Dredge. Photography John Colley.

MGC and V8 buying made safe

Remove the doubt of MGC/’B V8 buying

Buying Guide Get yourself a big-engined MG roadster or coupé with confidence

While MGB values have been on a steady decline of late, less ubiquitous variants have remained solid. This makes a decent MGC or ’BGT V8 seem a safe and compelling buy. MG replaced the old Austin- Healey 3000 with a ’B-based creation, shoehorning in the 3.0-litre straight-six from the Austin 3-Litre.

Buyers Guide MGC/’B V8

It followed up with a GT-only version powered by Rover’s V8 (a lighter engine than the B-series four), delivering further substance to match the looks. However, running them, especially the ’C, is not as straightforward as the evergreen ’B. We tap into the expertise of Former Glory’s Nigel Guild, V8 specialist Clive Wheatley, and Steve Hall of Hall’s Garage.

Which one to choose?

Introduced in 1967, the MGC combined the Austin 3-Litre’s straight-six within a modified MGB structure, in roadster and GT form. Torque was reassuring, but its 0-60mph time of 10sec was criticised. Production was cancelled after less than two years, in 1969.

In 1970 tuner Ken Costello began experimenting with the Rover V8 in the MGB chassis, modifying the front inner wings, steering assembly and exhaust manifolds, as well as forming a large oval bulge on the bonnet. These specials led MG to create its own version. Costello built MG’s production prototype, and continued to offer 180bhp versions for a few years after production of MG’s own 137bhp version GT V8 began. The MGB GT V8 debuted in 1973 in fastback-only, right-hand-drive 3.5-litre form, aimed at the Scimitar GTE, Triumph Stag and Datsun 240Z. Its 7.7sec to 60mph and 125mph didn’t come at the expense of handling balance or even fuel economy.

Despite being modified with plastic bumpers and a federal-spec ride height from 1975, the V8 was never sold in the US. Production ended in 1976, ahead of an anticipated V8-engined Triumph TR7 variant.


Rust can seriously weaken the monocoque bodyshell and bodges are common. While replacement MGB bodyshells are available (from £9000), there’s nothing on sale specifically for the ’C. The two models do share a lot of metalwork, although there are several key differences between the structural panels. The cost of a full-body restoration will outstrip the value of the car, so one popular solution is to import a rustfree ’C from the USA, then convert it to right-hand drive – and everything is available to do this. Budget £1000 for the parts and at least £300 to fit them.

Expect corrosion in the three-piece sill structures, which are often bodged. Proper repairs entail cutting off the front and rear wing sections (below the trim strip) or unbolting the front wings, but if taking the latter option, on a roadster the windscreen surround must be removed first. The whole operation will run to £1500 a side. So check for over-sills (including cosmetic stainless steel items) or correctly repaired outer sills masking rotten inners.

Be wary of plastic wheelarch liners because they may hide rot, but if the car looks cherished they’re probably there for the right reasons. Spring hangers corrode and next to the offside hanger is the battery tray (one each side on chrome-bumper cars), which rots. Check from underneath that the tray is intact and also ensure the floorpans are in good order.

The top of the fuel tank is corrugated to strengthen it, so water collects between it and the underside of the boot floor, where it’s attached. If you can smell fuel, assume the tank has perforated and needs replacing, at about £100 (10-gallon reproduction) or £200 (genuine 12-gallon) plus £100 fitting. Roadster and GT fuel tanks are interchangeable.

The GT’s double-skinned tailgate rots, as does any B or C’s scuttle, where it meets the base of the windscreen. Fixing rust here entails removing a roadster’s windscreen surround. Check the bottom of each door; new skins are £85, but a whole new door can be more cost-effective at £400, because getting the new skin to fit properly is so involved. MGC doors are the same as post-1968 MGB items. Budget four hours’ labour to get them painted and fitted.


The C’s six-cylinder engine is based on the Austin 3-Litre’s, but the valves, springs and sump are unique. The main components are identical and generally long-lived. After 80,000 miles the valve stem oil seals harden, so look for blue exhaust smoke as you accelerate through the gears. The rocker shafts also wear, resulting in a clattery top end. Don’t assume it’s just the valves needing adjustment. If a new rocker shaft is needed, a replacement is just £28.50 and it’s relatively easy to fit. The unstressed aluminium V8 should keep going forever if the oil and coolant have been changed regularly. The former is essential if the camshaft isn’t to wear prematurely, while the latter is needed to prevent the engine corroding internally, leading to blocked coolant passages.

If a rebuild is needed, parts for the V8 are plentiful and specialists easy to find, making it possible to rebuild one for £2500. The MGC’s straight-six, on the other hand, is an unusual engine with scarce parts, and the cost of a rebuild starts at £5500.


The C’s gearbox is based on the B’s, but the two aren’t interchangeable. First thing to go is usually the layshaft bearings, leading to whining. You can get the ’box rebuilt or fit a five-speed conversion with reduced transmission losses (so economy is improved), better ratios, quieter operation and the ability to perform a faster clutch change, but most owners prefer to keep things original. The V8’s gearbox also has a tough time, with wear common on second and third.

Driveline vibration points to wear in one or both of the propshaft universal joints; considerable gearstick movement suggests a worn or broken gearbox and/ or engine mountings. Replacing propshaft joints is easy and new ones won’t cost more than £110. Either gearbox will cost £1000 to replace. Engine and gearbox mountings are straightforward to replace, if weighty, so these jobs are very much DIY-friendly.


All MGCs and ’B V8s have a servo, two on some North American models with dual-circuit brakes. A lack of brake assistance means the seals have failed or there’s damage to the main diaphragm in the servo, not making use of the intended pressure variations that gives the assistance. This is often accompanied by an air leak ‘hiss’ and the engine will usually be less smooth. Bank on spending about £330 for a new unit.


The simple suspension is generally problem-free, although the kingpins will wear unless they’re greased every 3000 miles. Jack up the front of the car and try rocking the wheel at the top and bottom as somebody applies the footbrake. Any detectable movement means the kingpins need replacing – budget for £170 per pair plus fitting and allow for three hours’ labour for each side to carry out the job. Lever-arm dampers were fitted all round, which leak. It’s possible to swap to telescopics, but the ride will be harder. Some owners fit uprated front and rear anti-roll bars to sharpen up the handling, at a cost of around £100. Make sure all the rear tyre is visible – if it disappears into the wheelarch the springs need renewing (£60 plus a couple of hours’ labour per side).

Trim and electrics

All interior and exterior trim is available new. A hood plus fitting starts at £290, new seat covers cost £590 (leather) or £340 (vinyl), and carpet sets cost from £180-280. But a decent set of the V8’s unique Dunlop composite steel wheels will cost well over £1000. Until 1974, a pair of six-volt batteries were fitted, after which a 12v unit was installed. Neither system generally gives problems, but earthing glitches can occur because of poor connections between earth strap and body. The battery tray is behind the front seats (one on either side on six-volt cars); take the cover(s) off to check. Six-volt cars suffer from duff batteries if the car isn’t used regularly, because they drain each other, but converting to a single 12v battery is easy and cheap at around £50.

Owning an MGC/MGB GT V8

Frank Clemmey, London

‘I have a rare Downton-tuned MGC GT, but I’ve also owned a roadster and V8s beforehand too,’ says serial MG buyer Frank Clemmey. ‘My car was based on a very nice early example, is quicker than standard, and believed to be ex-works. The cylinder head is a different design from normal.

‘The elephant in the room with MGCs and V8s is parts availability. Things like the windscreen washer bottle and the radiator fan – a genuine ’C item is £79 – aren’t shared with the MGB. That said, it’s a better situation than it was 20-30 years ago, when the only parts for them came secondhand from old BMC dealers. Now it’s eBay and autojumbles.

Reproduction parts are inevitably of inferior quality. ‘I once modified a ’C roadster with V8 rear springs, but in truth a good set of radial tyres is key to good handling. Beware of modifications like a thicker anti-roll bar; they can cause chassis damage. It’s better to get to know the car over a few months, and learn to drive around its limitations.’

Tom Owen, Hertfordshire

Tom Owen bought his MGC eight years ago, having owned a couple of ’Bs and a Midget already. ‘I wanted something a bit different, for regular use,’ he explains. ‘I do 3000 to 5000 miles each year in it, including trips to Europe and around the UK. The ’C is an excellent touring car, thanks to its torquey engine – and mine has been made even better by swapping the front suspension for a ball-jointed set-up, courtesy of Doug Smith at MG Motorsport.

‘Set-up is crucial,’ says Tom. ‘You can’t just transfer MGB thinking. The floorpans forward of the car’s centre had to be redesigned, because the B’s beefy crossmember had to be swapped for a smaller, less sturdy item to provide clearance for the taller engine. As a result, the MGC’s front suspension also had to be changed, so the loads could be fed into the car’s structure in a different area from longitudinal torsion bars, running back to a central crossmember.

‘Because the floorpans were being redesigned, the opportunity was taken to widen the transmission tunnel so an automatic could be accommodated. At the same time, the radiator was moved forward eight inches, as well as being increased in size. Because of the extra weight over the front wheels, a less direct steering rack was fitted, offering 3.5 turns between locks instead of the B’s 2.9.’

Sponsored by Carole Nash Insurance

Peter McIlveney of specialist classic car insurer Carole Nash says: ‘Both the MGC & MGB V8 were underappreciated classics but are now highly collectable with values for both approaching £30k for the very best examples. Make sure you buy one with a solid ’shell; replacement/repair can be expensive. Originality is very important if you are looking for maximum return over 10 years. There’s a strong possibility that the recent surge in values will see a levelling out, so any future increase in values will be modest in comparison, but that shouldn’t put you off because ongoing maintenance over the same period should be lower than many classics of the same age and value.

Classic car insurance quotes: 0333 005 7541 or

1968 MGC GT — £19,950

I have owned this car for six years. It has been kept as original as possible. Engine all good with correct oil pressure; four-speed manual with working overdrive. Gearbox and final drive all good. Interior leather all original with fantastic patina. New wire wheels, stainless steel exhaust, new clutch just over 3k miles ago and will come with year’s MoT. Full Webasto sunroof.

Finding new interior trim parts for either ’C or V8 shouldn’t be a big problem. The MGC was only produced for two years, with roadsters like this being more desirable than GTs. MGC’s straight six is based on the Austin 3-Litre’s engine and is generally robust. MGC shares much of its structure with the later ’B GT V8, but their bodyshells are not interchangeable. New MGB bodyshells are available, but MGC ones are not

‘With the 3.0-litre straight six and V8, MG delivered further substance to match the looks’

What to pay

  • Late-model ‘rubber-bumper’ GTV8s in driver-condition start from £6500. Double this for the best.
  • £7500 will buy an average chrome-bumper GTV8 or CGT, rising to £15.5k-£16.5k for the best private sales.
  • C roadsters are the most desirable. Usable cars start at £10k; double that for concours examples.
  • Mint examples of any of these cars at dealerships will be stickered up at £22.5k-£26k. Once again, though, the rubber-bumper car is a bargain, topping out at £18,000 for the very best.
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