This is The Power Issue, so what better car for this slot than the Cobra 427? Launched in 1965, it was the world’s most powerful car in its day. It was also the fastest car tested by Autocar magazine that year, established the Guinness Book of Records’ fastest 0-100-0mph time, and held it for ages.

So the Shelby Cobra was the ultimate road rocket, even if it wasn’t as successful on the track as its forebear, the 289 MkII. But by 1965 the 289 racers were up against serious competition: the Cobra needed more power. Ever-wider wings clad a tubular chassis with coil springs instead of leafs and a race-developed 420bhp Ford 427ci (6997cc) V8. There were three derivations: Competition, Street/Competition and road cars.

Like many radical designs the 427 was not a sales success. It was never homologated by the FIA, as fewer than the required 100 cars were built, and the road cars were fitted with cheaper, more fragile 428 Police Interceptor engines. In total, 320 MkIII Cobra chassis/bodies were sent to Shelby and 27 were constructed and sold in Britain and Europe with the 289cu in engines, sold as AC 289s.

Of the 320 officially constructed 427 Cobras (the chassis numbers go up to 350 but 30 were unused), many were developed and raced with success by privateers and, as such, they remain some of the most mystical and therefore collectable of all Cobras. 

Leading specialist and expert Rod Leach (top)has dealt with over 350 Cobras since establishing his Nostalgia business in 1973. ‘There is a small but keen market in the UK and, while there is no typical 427 Cobra buyer, they are all great enthusiasts,’ he says.

‘Prices go up when the overall market is good and then stay there. Because these cars are so rare and enjoyable to drive they will never go down in value. Supply is still outstripped by demand.’ 

Originality is important, but some cars have had their 428 engine replaced with an authentic 427. ‘That’s acceptable, but the car must retain its four-speed gearbox,’ says Rod.

Cobras have risen steadily in value and are in huge demand, offering sensational performance with ease of maintenance.

‘Of course, you need to know exactly what you are buying because of all the replicas and fake cars out there. The absolutely crucial point is to double-check the chassis number,’ says Leach. ‘There is a worldwide registry for all the cars in the Shelby American Automobile Club tome that lists all the chassis numbers but it is not entirely gospel. Just to confuse the issue, a few cars share the same chassis number. This is inevitable because many of them were raced and crashed, resulting in rebuilds over the years. Also, there is a registry for Cobras within the British AC Owners Club.’

As with many sports and racing cars there are plenty of urban myths and stories about the provenance of some 427s, including Cobras being hidden by members of the mafia, etc. So you must consult a real expert before signing a (very) large cheque. In the good old days, crashed cars were junked and chassis numbers were transferred to new cars so you really need to know your onions. Provenance is all with a Cobra so it is essential that your research is done with forensic thoroughness. 

With original 1965 427s selling for up to a million pounds, the AC Cobra 427 MkIII S/C Continuation cars (as pictured here, road-registered as a 1966 Historic Vehicle) seem like good value at about half the cost. With cast-iron AC Cars Ltd certification (and FIA eligiblity), this 427 appears and drives exactly like the 1960s original. Only ten were built in total during the early 1990s.

Because what you’re really buying is provenance, and because Cobras are highly valued, this isn’t the kind of buying guide that warns of frilly wheelarches and blue smoke on start-up. That said, all Cobras feature aluminium bodywork, so watch for stress cracks and dents. A complete body rebuild costs around £100,000.

But the really good news is that these powerful cars are easy to run and maintain. All components are available, with mechanical parts well priced in American catalogues. Things get expensive with performance components such as heads, high-rise manifolds and Weber carburettors, but figure on a price around £10,000 for a full engine rebuild by a specialist such as Mathwall Engineering. 

The Shelby Cobra 427 is one of the rarest and most powerful road cars ever manufactured. Original cars can be worth more than £1 million, so it is essential to know exactly what you are purchasing. Speak to the AC Owners Club and Bill Shepherd who, although he now specialises in Mustangs, has a great wealth of experience racing and preparing Cobras, at www.billshepherdmustang.com; +44 (0)1932 340888. 

But most definitely talk with Rod Leach, who is a fund of information on the complicated history of this great marque. The story of AC itself, the Cobra, Shelby, lawsuits, the various owners of the company and the rights to the name, Continuation Cobras, Autokraft, replicas, kit cars, etc, etc – it’s a snake pit that can catch out even the most agile researcher. 

Make sure you don’t get bitten.