Porsche 914 and 917 at Spa in 1970.
I didn't shoot this, but this shot is one of my favorites. It's not particularly well taken but the content is superb and it's so damn authentic. I originally found it in this book which did not cite the photographer.
The 917K is a predictable choice for 'favorite all-time race car' but there are about a billion reasons why which I won't go into. Look how tiny it is — the diminutive Porsche 914 next to it actually towers above it. It's shocking how well they used the tools and materials of 1970 to build something that looks from the future. It's still gorgeous today and looks epic inexplicably parked backwards at Spa. The rich tones from the film and the awesome vintage advertising lettering sucks me into this image every time.
Note how much gas/oil sponsorship is going on here. Shell, Texaco, BP, Gulf, Chevron, Castrol and Esso, and I'm probably missing some.