When my brother and I got low-end 10-speed Bianchi Corsas for Christmas 1962, one of the neighborhood kids got a 12-speed Campi, which was almost identical to our Bianchis except for the longer rear axle and the green paint job. Six-speed freewheels became standard in the very late 1970s into the early 1980s.

Get a Regina if you really crave correctness or are worried about Italian/English thread "combatibility," but get a 7-speed SunTour, Shimano, or SRAM for most positive downshifts and a greater choice of ratios. My favorite low gear cog is a hard-to-find 26, which works with almost any short-cage derailleur, while providing a very nice granny with a typical 42T inside chainring. I changed the Bianchi from 52-42 / 13-15-17-19-21-23 to 50-42 / 14-16-18-20-23-26, picking up a seldom-used but so-nice-to-have bottom gear.