My first thought was that an event sponsor was maybe blocking the visibility of a rival's product, perhaps Shell as they featured prominently at the time. However, checking the Ford France car from 1967 on page 99 of Ford au Mans, that theory is blown out of the water by the image of the Hawkins/Bucknum car on the facing page which shows a prominently placed BP sign trackside on the exit to Indianapolis.
If it were a single race then it could be put down to a printing cock-up, but at least two years running? I know it's trivial but it's been niggling at me for years!
