Seeking a whole series of juvenile fiction books on car racing from the 1960s or 70s. The main character raced at Le Mans and the Baja 500, among other races. Devoured these books when I was young, but can't remember any of the titles or the author.
A picture book in which several small children build a working car out of stuff they find. For the headlights, they fill a jar with fireflies.