Ferrari built a series of highly-tuned race engines based on the specifications of the cars campaigned in the Mille Miglia races. These cars were equipped with three four – barrel carburetors. Again the coffee can assembly was used with the satin painted steel tops and bottoms with the nickel – plated perforated steel sides. These air cleaners were made by F.I.S.P.A and used a single small aluminum tag, 11mmx60mm, riveted to the perforated side panel. Four-Barrel “MM” F.I.S.P.A air cleaner tag.
The next generation of tags was crescent shaped with a blue field and black writing. These were introduced in the mid-1950s and were used on both the individual coffee can type filters and the new “Three-in-One” type air cleaners which had a single long housing that contained all three individual filter elements. These tags had a chord length between the rivets of 51mm. Early F.I.S.P.A blue and black crescent shaped tags with the 51mm chord length.