Isotta Fraschini "Special" made 1921 and raced by Alfieri Maserati (especially in 1922).<a rel="nofollow" class="external autonumber" href="http://www.kolumbus.fi/leif.snellman/hcw2.htm">[1]</a> It was an Isotta frame, Itala rear axle, 6.3 litre Hispano-Suiza engine etc.<a rel="nofollow" class="external autonumber" href="https://motorvalley.it/en/story/maserati-the-origins-of-trident/">[2]</a> Here with his brother Ernesto. They raced at Mugello in very similar car (#5) the same year.
Unknown photographer
<a rel="nofollow" class="external autonumber" href="https://ezgif.com/webp-to-png/ezgif-2-3631e33372f6.jpg">[3]</a>