Price: £134,995 | Year: 1968 | Engine: 6,997 cc V8, 355 bhp

You're looking at a piece of American motoring history. This slightly battered Mustang, in need of a full overhaul, isn't really a Mustang at all. Its all-original condition — from the rust to the untouched 1960s interior — is part of a remarkable story involving long-term storage and rediscovery. This Shelby Mustang GT500 is one of just over 2,000 made, taking Ford's most famous coupe and adding a thundering seven litre V8 to give it the scintillating performance that the design always deserved. All of this makes this slightly rusted sports car a unique example of an all-time American classic.

This is an all-original 1960s muscle car. The GT500's paintwork is unrestored, with touch-ups to the Wimbledon White exterior believed to date from the 1970s. The Shelby-applied blue side stripes are present and correct. Surface rust is testimony to the car's original condition. There's even a factory production line ticket as part of its provenance, important proof since there are many fake GT500s to be found. Genuine Shelby Mustangs, like this one, were the work of Carroll Shelby's Shelby American company, most famous for producing the Le Mans winning Ford GT40. The GT500 — the words "Mustang" or "Ford" never appearing on its badging — is regarded as the pinnacle of Shelby's work on the Mustang, making this car all the more special.

Open a door to an interior world of 1960s sports car glamour. The period black vinyl that forms much of the coverings is virtually unmarked, showing only the desirable patina of age, present also on the chrome work and wood veneer. There are Shelby logos - featuring the firm's famous cobra - on the centre armrest, steering wheel boss and even on the seat belt buckles as if to emphasise what this car really is. This GT500 also features the optional rear Sport Deck seat, recommended for short journeys only. Front accommodation is in generous chairs, the better to support its occupants as the car's huge V8 took it to 60 mph in just over five seconds, an impressive result even today.

Under the bonnet is Shelby American’s real contribution to this car: the huge V8 shoehorned into the engine bay. The bonnet has the factory fitted vents to help the V8 breathe as this muscle car pushes its way forward at an unfeasible speed for its era and for a production car. Transmission is automatic but there is so much power in each gear that it is more or less irrelevant.

This GT500's history is as fascinating as the car itself. The second owners, who bought the car in 1974, fell on hard times and gave it back to the dealer they'd bought it from. On their behalf, the dealer stored the GT500. The car had just 70,000 miles on the clock, as it still does today, because the GT500 was inexplicably never reclaimed. It remained, largely forgotten, in its storage unit until the car dealer's niece and nephew found it after the dealer died in 2014. They left it as it was, but sold it on.

The Shelby Mustang GT500 is now for sale again, its price reflecting the value of unrepeatable authenticity. Apart from some light mechanical work the GT500 remains as it was when it emerged from its long slumber and will require, at the least, a mechanical overhaul before it can truly rumble into life again. A new owner could further restore it to concours condition, or honour its history and keep it as far as possible as it is in these revealing photographs, a great car bearing the honest marks of its age. Fit for a museum, or — better still — a swift journey down Highway One.

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