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Long awaited MGB upgrade with more sting, was a sales disaster despite its performance and Aston-like character. Only available as a GT offi cially, but there are many DIY conversions around - some good, some bad. They remain remarkable value 40 years after launch, but the gap between a V8 and a standard MGB GT is growing
Ever since the MGB was launched back in 1962, enthusiasts craved for more power – how hard could it be for MG to make a B with more sting? And yet it failed – twice! The fi rst attempt was the six-cylinder MGC, but that died a death after just 8999 sales. What was needed ways a V8 everybody said – and when MG did fi nally launch such a car 40 years ago this summer, it managed to shift less than 3000 of them!
And, given the MG’s comparative rarity, the V8 rarely costs much more than a normal MGB to buy and they are just as easy and low cost to own and maintain.
Clearly this won’t go on for ever, so if you’ve ever wanted the factory V8-powered MGB then don’t leave it another decade longer. The time to buy one is now!
HISTORY
1971 Abingdon had been trying to shoehorn a V8 into the MGB for years (some say as early as ‘67, but offi cially since 1971) and it is said that they fi rst tried that wonderful Daimler V8 unit. It was Mini racer
Ken Costello who showed the factory the way forward and who continued to make his own bespoke conversions up until quite recently.
1973 Unlike Costello, MG made do with the lower tune 137bhp Range Rover-spec V8, allied to an MGC gearbox but with closer ratios and overdrive active only in top gear. The MGB shell needed minimal changes to make the V8 fi t and as it was 40lb lighter than the cast iron B-Series, it helped alter weight distribution from 47.8/52.2 to a more equal 49.4/50.6.
In contrast to the MGC, the V8 retained the conventional MGB front suspension set-up, although the ride height was hiked by an inch in the process, pre-empting what BLMC had to do to the MGB a year later… MG engineers wanted to go further developing the aged chassis but the only concession were ‘Police’ spec rear leaf springs.
1975 This was the year that the V8 received those infamous rubber bumpers along with the MGB and Midget despite the V8 never being exported to the USA!
1976 After the disastrous MGC debacle, BLMC hoped that by giving MG fans what they really, really wanted all would be forgiven, yet the BGTV8 was given a lukewarm reception and pensioned off in ‘76 after just 2591 cars were made– that’s about a quarter of what the unloved MGC achieved. However, survival rate is brilliant says the MG V8 register, with some 1900 still around.
DRIVING AND PRESS COMMENTS
If truth be told, the chief reason that the car failed to sell well is that BL launched the car just as the Energy Crisis of the 1970s kicked off, fi rst with the Middle East War and then resultant fuel shortages – hardly the ideal platform to launch a V8-powered sports car, was it?
Nevertheless, despite the recipe being right (and it has to be said that the offi cial car was better developed than the Costello effort) many critics felt that the car had come to market fi ve years too late and all the introduction of the V8 engine did was to highlight the shortcomings of the ageing 11 year old MGB. It’s a different story 40 years on, where that ‘vintage’ feel is an asset.
Its two-star (low compression) performance is not an issue and a good one will still show many moderns a clean pair of rear tyres, (0-60mph in 7.7 seconds and 125mph according to Motor) and such is the torque on tap there’s little need for gear changing – a bit like the Jag V12. The standard overdrive gives a lovely long legged 28.5mph/1000rpm gait – strangely there was no automatic option.
Improved weight distribution, even against the normal MGB, means that the bigger engine didn’t hurt the handling like it did on the MGC. However, the V8 still didn’t handle as predictably as the four-cylinder MGB, it was said. Road tests at the time put this down to the stiff rear suspension and added ride height. However, other known MGB traits such as the hard ride, wind noise (which one road test said made fast cruising “a misery”), poor heating and ventilation and lack of overall refi nement are now of less hindrance than when the car was new.
And it was these defi ciencies which soured the car. Motor in ‘73 claimed that, “Telling BL what they ought to do has become a national pastime”, adding that “initial reaction to the car was quite enthusiastic” although you have to bear in mind that hotted-up MGBs, some with V8s, were quite common by late ‘73.
“So appealing is the BV8 package that, when the failings start to show themselves, there is a sense of disappointment… considering how much more the BV8 is (£2300) one would have thought that British Leyland could have come up with a more modern layout.” It concluded that, “As a poor man’s Aston Martin V8 the new MG has a charm and, with improvements, could even be a worthy alternative”.
Rival weekly Autocar thought the handling not as good as the MGB, criticised the car’s general aged design, illogical high price asked (about the same as a Scimitar GTE) and it signed off by saying that if the car did succeed in the showrooms, “It will be mainly due to the excellent Rover V8 for which praise cannot be too high”. The long gone Competition Car reckoned it was a bit like the Sunbeam Tiger killed off fi ve years earlier in ‘67 and added: “The old bottle hardly does justice to the new wine.” Australian magazine Wheels felt all that the addition of a V8 had done was to show that the car was now very long in the teeth. Motor Sport went along with those sentiments, adding that if the car had been launched instead of the MGC and continually developed, then by 1973 it would have been ”Another world beater”. We couldn’t agree more…
PRICES
The days when a V8 would sell for the same price as a MGBGT are going, says Croydon Classics’ James Barton, and he reckons that a top car will now sell for double the asking price of a normal 1.8 – say around £16,000, which is on par with the reborn MGC GT. However, despite their rarity due to less than 2600 being made, you do see them sell for less, so shop around. £8000 should still net a pretty good example we feel. Home-made V8s are usually worth less than the real thing, but Costello conversions can command a premium over a factory car, although it depends how much was spent on the car in the first place as they were built to individual requirements.
IMPROVEMENTS
For many, a standard V8 is quick enough, so the car just needs the chassis tweaking.
Lever arm dampers were fitted but it’s possible to swap to telescopics. It works well but the ride will be even harder. To really sharpen up the handling it’s worth fitting uprated front and rear anti-roll bars with poly bushes although again the ride will be made a lot harsher.
Servo-assisted brakes were fitted from the outset and this essentially standard MGB set up copes well enough, but uprated EBC pads and better discs are always a wise move for modern motoring.
Alternatively you can fit the more exotic MGR V8 front suspension and better brakes, which is expensive but effective.
Even if you keep the engine standard, electronic ignition and an uprated radiator are worthy mods, the former really helping the performance says the V8 Register.
As the basic V8 engine evolved into 4.6-litres over the years, in terms of power you can really give this B some real sting while a Rover SD1 five-speed can be fitted. MGOC sells a complete nut and bolt kit to do this but it costs some £2000.
What To Look For
GENERAL
- The MGB GT V8 is extremely well supported by the MG Car Club with its own registrar and it’s as easy to repair and maintain as a normal MGB, plus parts supply is just as good.
- Beware of fake Costellos! It’s not unknown for homespun conversions to be passed off as Ken’s work. Ask to see a history of the car and look for unique Costello badging. Similarly, you will find many DIY conversions and their standard of workmanship needs scrutinising. A lot are excellent but others shouldn’t be on the road, reckons V8 expert Clive Wheatley…
- Swapping those rubber bumpers (only 735 were made) that add 70lb to the car’s weight isn’t a simple job as there’s some fairly major bodywork surgery involved. It can be costly too if a professional does it; bank on £1500 or more.
BODY AND CHASSIS
- The BV8’s monocoque is a real rust haven, and there are plenty of places where you’re likely to find rot; bodged repairs are also likely. But if the worst happens and the ‘shell really is beyond economical repair, you can buy a Heritage shell. If you want to do it cheaper, a second-hand rubber bumper shell is required.
- The sills rot and are bodger’s delight, because repairing them properly is a convoluted process. Take a look from underneath and see that everything lines up properly. If the door windows clip rear post that’s a sign of poorly fitted sills (check inner sills too).
- Look for soft inner wings – press the panel in the engine bay as a quick check. Inspect where steering rack is located. This can stress crack. Unless you know MGBs this can be missed, even by MOT testers. Others areas include front scuttle, fl lors, rear axle and hangers, valances, tailgate and the petrol tank.
SUSPENSION
- The MGB’s simple suspension set up coped okay with V8 power and doesn’t generally give problems, except for the kingpins; a common MG fault.
- The front wishbone bushes also perish and collapse. Always ensure that proper uprated V8 ones are used over the standard MGB sort.
- Steering is heavy but should be precise with no wandering or excessive freeplay. There’s even an MGOC power steering conversion kit. Somewhat easier amd cheaper are castor reduction kits which will lighten up the standard set-up.
TRANSMISSION
- The V8 used a modified MGC gearbox with overdrive only on top (although some cars sneaked through with it operating on third, too says V8 Register). Check for undue noise, jumping out of gear and sheer wear. It is vital to use correct 20/50 engine oil in the standard overdrive.
- Clutch problems usually centre around the carbon fibre release bearing breaking up. Also make sure the pedal isn’t spongy. If it is, the hydraulics are on their way out.
- Under all that power the MGB-derived rear axle may well have wilted and become noisy and sloppy. Bank on a few hundred for a recon unit or you can have a limited slip alternative from MGOC costing over £700 to improve the average traction.
Three Of A Kind

TRIUMPH STAG
In-house rival to the MG and also V8 powered with more bhp but less go. Hard/soft top instead of a hatchback, initially the Stag was dodgy but now they are well sorted. Still good value and there’s a brilliant specialist and club back up. Of course many Stags were converted to similar Rover V8 power and these are good done right but are now worth less than factory spec cars.
MGC
People are seeing the MGC in a new light. The straight six is slightly more powerful than the Range Rover tune V8 but latter has more torque. Handling, on modern tyres at correct pressures, is about the same as the V8 – both need improving and can easily be done – but ride is inherently better. Unlike the V8 the MGC can be had in roadster and automatic forms and values are around the same as a BGT V8.
MG RV8
Rather late in the day MG Rover launched the roadster V8 – almost two decades after the independent MG company folded. Based upon the Heritage bodyshell with a full fat 190bhp and totally reworked chassis, without doubt it’s the best sorted V8 MGB as well as the most luxurious. The MG RV8 feels like a cross between a Morgan and a TVR and prices are similar to MGB GT V8 levels.Verdict
Not before time the MGBGT V8 is being given due credit as a B with real sting and the gap in values will only widen against a 1.8 as the years go by, thanks to their rarity, but at least they cost about the same to
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