I've been following this puzzle since it was first posted - I don't know the answer, however. The photo is distorted by shutter speed and possibly an attempt to "pan", but obviously it is clearly a Maserati. What confused me was the size of the air intake, which is unlike any normal Maserati model, but maybe it was enlarged to cope with the extreme heat of South America. The twin exhaust pipes raise a puzzle - all 4CLT models had a 1.5-litre 4-cylinder engine with one exhaust. The following A6GCM 2-litre 6-cylinder cars had twin exhausts, but this car is earlier. I think it could be a car which was owned by Scuderia Achille Varzi who in 1950 fitted an engine from an A6GCS sports car into an old 4CLT. It actually won at Angouleme in 1950 driven by Fangio, but I can find no photo to prove my claim.
The driver is almost impossible to see in the photo - nearly all drivers for the Scuderia were from Argentina or Uruguay, although others such as Toni Branca (Switzerland) and Bira (Siam/Thailand) drove from time to time. That part of South America has a very large ethnic Italian population, and Italian names are commonplace. This is a bit of a guess - Adriano Malusardi?
