In the same #123 issue of 4R that covers the Panhard powered Fiat 500, there is mentioned a list of entries for the ‘Mostra delle vetture de Competizione” held in Turin from 26/02-6/03/1966 in the Musea dell’Automobile.
In that list, there are present 2 potential Fiat 500 derivates that are not present in your book.
- Giannini 500 F turismo competizione: This is a car that I also can’t find back in the Giannini book by Enzo Altorio. Or is this the same car as the 500 TV (S) / 590 GT (S)?
- C.A.S.E.A. 875 Monza: I don’t know if there is any Fiat relation, but for me that counts also for the Marsengo 875 Torino prototipo which is included in your list.
About the names Giannini used.
I suppose 'TV' stands for Turismo Veloce, 'GT' for Gran Turismo, 'GP' for Gran Prix, 'S' for Sport, 'L' for Lusso, 'R' for Rally and 'EC' for Economica.
But where are 'MT' and 'NP' standing for?