Andre Pradeau, from Limoges in France, built a series of small capacity cars during the 1950s and early '60s, one of which used a JAP 500 engine. Sadly we do not have any details of this car, or whether it still exists.

This photo is of  later car, a prototype for the Formula IV which was killed off by the introduction of Formule Bleu which used Renault engines.

If anyone has any more details, please get in touch.