Peugeot 203 engine was 1290 cc. Was its displacement decreased to less than 1100 cc ?
Sorry oko94, I don't know any more. I have just rechecked my source and there is no reference to the engine size. I also think I may have been wrong about the car taking part in FJ and F3 events. It is more likely that it raced in single-seater events against cars with much bigger engines so possibly the engine was not reduced in size in order to qualify for the F3 category.
My apologies for providing misleading information.
(Here's another photo of the car taken in period, which shows the type of race it entered. Apparently this race was for Group O & M cars, which is new to me!)