To all appearances, a Porsche 906 is an exotic sports prototype like any other of its vintage. Svelte, curvaceous, lightly crude when you look at the details. Big bulbous lights flow with the bodywork, a bubble cockpit emerges from the centre. The cabin section slopes into the engine compartment in which six throttle bodies can be seen coming up for air. It’s quite unlike anything you might have found in a Porsche dealership at the time in that it was fit for its one and only purpose – racing.