SAV might still exist. Here's the web site of an autobus company with the same name in Cuneo. Maybe contacting them and asking them about their history reveals more information about the type of bus they used.
Originally Posted by 58_spyder
I have nothing on the SAV autobus company. Are you able to tell what is on the site of the bus?
The caption of the original image (see here) reads "Il Bus della Solvay da San Carlo" (both Solvay and San Carlo are south of Livorno and near San Vincenzo). I'm guessing the script on the side of the bus may read something like "Galdi Davide - San Vinzenzo" (which might be the name of the owner or operator of the bus).
'63 2600 Touring Spider (AR 191437, the car that started the 2000/2600 International Register, reassembly in progress)
ex-'65 2600 SZ (AR 856043, resto project)
Maintainer of a 2600 SZ register (not the Dutch one).