Re:
...and now I have a new project.
Until a somebody corrects me i'm going with a 1970 Bianchi, maybe Specialissima.
I feel confident that the bb shell was replaced sometime after 1978 (given the winged "C"), water bottle bosses were probably added at that time, then repainted. The work around the bb shell isn't nearly as nice as the rest of the frame, bit of a shame really.
In any case it's a lovely bike to look at and will be a fun rebuild, aside from the headset of course...