Price: On Application | Year: 1972 | Engine: 2.4 litre flat six, 155 bhp

Here's an eye-catching piece of Porsche perfection with a distinct quirk. This delightful canary yellow 911 Oelkappe is from the classic early years of this greatest of everyday sports cars. And it's also evidence of Porsche's ongoing quest to make their products the very best they can possibly be.

Early examples of the 911 had swiftly showed the drawback of having so much weight – in the form of the engine – beyond the rear wheels. Red-faced drivers found their new cars rather too eager to step out around corners, and a spin in your out-of-the-box sports car is rarely a good thing. 

Porsche engineers came up with a partial fix: they moved the oil tank from behind the rear wheels to just ahead of them to help even out weight distribution, then helpfully added an oil filler with accompanying flap in the right rear quarter panel, just where you might expect a petrol filler flap to be. The inevitable result was that careless owners put petrol in the oil tank, with expensive consequences, when, as any Porsche aficionado will tell you, on a classic 911 the actual petrol filler flap is in a front wing. At Porsche, they like to construct their own logic.

Just 1523 of these so called "Oelkappe" models were produced before Porsche, weary perhaps of telling owners to read the handbook properly, moved the oil tank back for the next model year. The immaculate example you see here is one of those 1523 cars. The canary yellow paintwork has been newly refreshed and the 911 wears eye-catching black Fuchs alloys for a stealth street look. 

The interior features the classic 911 five dial dash and an evocative period Momo wood-rimmed steering wheel. The non-standard front bumper is in the 911 RS style and the car features a five speed gearbox. The oil filler flap is present and correct.

This idiosyncratic piece of Porsche history is on sale through Timeless Garage of Lisbon. While price isn't disclosed, previous sales suggest that you'd need to pack at least £70,000 in your baggage as you head to Portugal to pick up the 911, if you want to sign off on the deal, climb in and drive home. Just remember where to put the petrol.

Discover more Porsche perfection in the form of this classic 1972 Porsche 911.

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