Triumph GT6: buying guide and review (1966-1973)

There’s a certain honesty and simplicity to the Triumph GT6 that has made it a desirable choice for classic motorists on a relatively modest budget. After all, a  six-cylinder engine and handsome looks didn’t have to cost the Earth, even if they usually did... 

It might be a bit of cliche, but the ‘poor man’s E-type’ nickname given to the car when it was launched in 1966 still stands up today. Prices are still relatively affordable, and it’s relatively quick and enjoyable to drive thanks to that silky-smooth six. Thanks to a thriving club and specialist scene, parts are cheap and support is plentiful. Restorations are a viable DIY proposition too, thanks to the seperate chassis and simple mechanicals.  

Although prototypes based on the four-cylinder Spitfire with the Michelotti-styled GT bodywork had been kicking around since 1963, the extra weight dulled performance considerably, putting the project on ice. In 1964, the company tried fitting the Vitesse’s 1600cc six-cylinder engine to the GT, and now reinvigorated by the idea, development of the GT6 continued apace.

By the time the GT6 actually saw the light of day in 1966, the engine had grown in size to 2.0-litres, producing around 95bhp. Hardly Earth shattering, but it was enough for a top speed of 108mph and acceleration to keep most entertained. 

Like the Jaguar E-type, the Triumph GT6 is all engine up front - a defining characteristic of the car. Based on the Spitfire underpinnings, early cars were renowned for particularly tricky handling, although this was ironed out in the Mk2 and Mk3 cars.

Which one to buy?

There’s a good selection of cars on the market, and most cars have been restored once or twice in their time. As to which model to go for, you effectively have three options: Mk1, Mk2 and Mk3. 

The earliest cars, built between 1966-1968, are the rarest examples. Although almost 16,000 of these were built, very few original examples can be found today. A lot will have been upgraded and modified in period, and getting hold of original spares and parts is quite tricky. 

For many, the Mk2 cars are actually the best compromise, as a new Rotoflex suspension system improved handling while the styling remained more classic. The Series 3 cars are the most evolved, with a new style borrowed from the uprated Spitfire, with the later cars getting an even better ‘swing spring’ set-up.

Performance and specs 

Engine 1998cc in-line six-cylinder

Power 98bhp @ 5300rpm

Torque 108lb ft @ 3000rpm

Top speed 112mph 

0-60mph 10.1 seconds

Fuel consumption 20.2mpg 

Gearbox Four-speed manual

Dimensions and weight 

Wheelbase 2108mm

Length 3632mm

Width 1448mm

Height 1194mm

Kerb weight 864kg 

Common problems

• The Triumph straight-six engine is famed for its oil leaks, and rattles at start up. These ‘characteristics’ can be engineered out without too much difficulty or expense. If looked after with oil changes every 6000 miles it’ll last 100,000 miles between rebuilds.

• All parts are readily available, and it’s an easy engine to cut your teeth on if you’re buying a restoration project. Renew all oil seals while you have it apart, as it will save taking the engine out again later. 

• If the original canister type oil filter is still fitted it’s worth investing £40 on a spin-on conversion. That will allow you to fit a modern filter with a non-return valve on it, meaning the bearings won’t be starved of oil when you start it up, eliminating that start up rattle.

• The GT6’s weakest link is its final drive, although if it’s well looked after there’s no reason for it to leave you stranded. 

• The problem lies with the universal joints and diff, which can struggle to cope with the 2.0-litre engine’s torque. They’re an evolution of the Herald units – which in turn had evolved from Standard units of years before.

• Make sure the diff and gearbox aren’t especially noisy – the gearbox is usually sturdy, but the diff will whine loudly if it’s getting tired.

• If there’s clonking from the transmission as you manouevre backwards and forwards it’s probably because some of the universal joints need replacing. 

• The plastic bushes in the remote gearchange mechanism wear out eventually, but fitting a new set is cheap and. 

• No GT6 had overdrive fitted as standard, but it was available as a factory-fitted option. Few Mk1 owners ticked the box but it became increasingly popular and most Mk3s owners specified it. 

• A lot of cars have it nowadays because it’s easy enough to retro-fit – and overdrive is worthwhile because it’s more relaxed driving a car equipped with it.

• Unusually, when new a GT6 with overdrive was no more relaxing to drive than one without. That’s because the final drive ratio of cars not equipped with overdrive was lowered to 3.27:1 from the previous 3.89:1, to improve acceleration rather than make high-speed cruising more relaxed.

• If overdrive is fitted but it’s not working, the chances are that it’s only an electrical connection somewhere that’s playing up or a lack of oil pressure because the unit’s internal filter needs a clean. 

• If it’s anything more serious, rebuilds are best left to a specialist, but if it has called it a day you can buy a rebuilt overdrive for £150 on an exchange basis. 

• If the car is fitted with a rubber doughnut Rotoflex coupling, make sure the coupling isn’t about to disintegrate. Even the genuine Metalastik couplings last no more than 35,000 miles and cost at least £40 each side.

• If the car doesn’t have Rotoflex couplings things are a lot simpler as you’ve then only got to be concerned with the rear bearings which last well and cost £18 per side.

• The main thing to check with the rear suspension is the condition of the transverse leaf spring, which sags with age. Replacing it isn’t especially pricey at around £100 (£80 for Rotoflex) but it can be a devil of a job unless you’ve got a spring lifter to help you. 

• If you have the swing spring (late Mk3) it will probably only need new rubber pads between the leaves. There’s also a rubber bush at each end of the leaf spring along with bushes in the radius arms which locate the back axle and in each of the dampers. 

• Thankfully the front suspension doesn’t give many problems. Sometimes the drop links that hold the anti-roll bar to the lower wishbone can break off.

• Tired springs or dampers might need to be replaced, but the job is easy and the costs are low. The wishbones are fitted with rubber bushes, as are the anti-roll bar mounts and the steering rack mountings. These can all be replaced with polyurethane items.

• Although the Herald family of cars has a reputation for suffering from irritable trunnion syndrome, it’s only if the car has been neglected that you’re likely to have problems. If they’ve been lubricated as specified in the owner’s manual, they’ll be fine. But few owners know that every 6000 miles EP90 is supposed to be pumped in (not grease). 

• The trunnions themselves are brass and don’t give problems – it’s the cast iron vertical link which threads into the trunnion which breaks. 

• Pressed steel wheels were fitted to all GT6s as standard, but by now many have been swapped for alloys or wires. Because the GT6 has an unusual offset it’s easy to buy wheels that suffer from clearance problems, so check that they’re not rubbing if aftermarket wheels are fitted. 

• If wire wheels have been put on, make sure that the spokes haven’t broken and that the splines haven’t worn. The widest tyres that will comfortably fit a GT6 are 175s.

• Unless the example you’re looking at has been really cherished, it will have had some remedial work performed on it at some point. That’s no problem if it’s been done properly, but if a full-scale restoration has been attempted, and the body and chassis haven’t been separated, the work clearly hasn’t been done properly. 

• It’s not so much the bodyshell that’s the problem as the chassis. The rear can be easily repaired, but ensure the front is aligned properly. The bonnet mountings (which are available new) are the most important here, because if they’re not lined up correctly you’ll never get the bonnet to line up properly.

• The bodywork itself consists of two main sections: the front end (bonnet top, nose and front wings) and the main bodyshell (a tub made of the roof, floorpans and rear wings). The tailgate and doors attach to the tub and it’s all put together like an overgrown Meccano kit – handy for taking apart and putting back together.

• Although it’s a good idea buying a bodyshell that’s not full of holes, it’s the chassis that gives the GT6 most of its strength. Thanks to the engine having a tendency to spray the underside of the car with oil, there’s a good chance that the metal has been reasonably well preserved towards the front. 

• It’s worth buying replacement outriggers to patch up the chassis if the main rails are sound, but if the frame has rusted away comprehensively you’ll be better off getting a replacement – you won’t find a new one anywhere, but usable second hand ones can be picked up readily for £100 or so. 

• Even if the chassis doesn’t need any work, there’s a good chance the bodywork will. The first areas to check are the sills, floors and wheelarches. 

• The GT6’s sills are structural and if they along with the floorpans haven’t been replaced yet, the chances are they will need renewing before long. 

• Nearly all body body panels are available new and are fairly easy to fit, but if somebody else has already done this, make sure the panels line up.

• Check under the false boot floor where the metal floor meets the arch – the passenger side is hidden under the petrol tank but the off-side will give a good idea of condition. 

• All versions have a habit of corroding between the rear lights, and as new panels are not available you’ll have to be handy with the MIG. 

• Doors are rot-prone but thankfully the shells usually remain sound needing only a new skin. 

• Other rot spots include the bottom of the hatch aperture which fills with water then rots out and the double-skinned leading edge of the roof where it meets the windscreen surround – condensation collects in the seam and rots from the inside out. 

• It’s quite common for the master cylinders on the bulkhead to leak brake fluid onto the metal panels below. Once this has stripped the paint, corrosion will follow, but the use of a silicone based brake fluid will avoid this.

• Even if there’s no discernible rust anywhere, the car may have been in an impact at some point. Poor shutlines are common on otherwise well-restored GT6s because aligning the panels can be very tricky. 

• The easiest way of telling if the car has been shunted is to look at the chassis rails in front of the engine, which may be crumpled. Even if the car has been in a fairly big accident, if the chassis has been replaced properly along with the necessary panelwork, there’s no need to worry. That’s the beauty of not using a monocoque.

• If the wiring has been hacked about you can buy a new loom for £170 and the few ancillaries that are fitted, such as wiper motor, alternator and starter motor are cheap to buy. 

• If you find a GT6 with a completely trashed interior but it’s on offer at a knock-down price, you’re in luck as it’s possible to buy new carpets, door panels and seat covers for a reasonable. 

Model history

1966: GT6 debuts at Earl’s Court motor show, with 95bhp 1998cc Vitesse engine. Overdrive was optional while bumpers and lighting are carried over from the Spitfire. 

1968: The Mk2 GT6 arrives with a new dashboard, revised cylinder head and tweaked rear suspension. The straight-six’s top end is from the TR5, to breathe more easily, while the rear suspension adopts Rotoflex couplings and wishbones in the rear suspension. Styling adjustments include the removal of the louvres in the side of the bonnet, raised bumpers front and rear and Rostyle wheel trims. 

1969: Better interior padding and an improved steering wheel, and the structure is strengthened to cope with tougher US crash regulations. 

1970: The Mk3 GT6 goes on sale little changed from its predecessor. Deseamed shark-nosed bonnet and the rear panels are updated with the family cut-away tail which incorporates less chrome. There are no significant changes under the skin. 

1973: A brake servo is fitted, the rear brakes are increased in size and the rear suspension’s Rotoflex couplings disappear, with the swing-spring rear axle later to be used on the Spitfire being fitted instead. Vinyl replaces the brushed nylon seat covers and head restraints plus tinted glass are fitted.

Owners clubs, forums and websites

• www.tssc.org.uk

• club.triumph.org.uk

• www.rimmerbros.co.uk

• www.triumphshop.co.uk

Summary and prices

With low parts prices, strong spares availability and the car’s Meccano-like construction, even the tattiest GT6 can be revived – as long as you’ve got the patience. Even better is the fact that once built, the GT6 is great fun to drive – and it’s even more fun if you mate a Spitfire with a GT6 to produce the drop-top that Triumph should have built. 

The best condition Mk1 and Mk2 examples generally cost around the £12,000 mark, although there are many more affordable examples from about £8000. Rough and ready cars can still be picked up from £5000, while projects are still available for about £1500. Add about 10 per cent for Mk3 cars, while cars with no overdrive fitted are worth slightly less.