Looks like possibly a 1980's -1990's Japanese-built Bianchi (more pics would definitely help pin down the model). Many of these were as good (and some think better) than their Italian-built cousins. You many find a frame material sticker on the seat tube saying "Ishiwata", "Tange", or "Bianchi Superset". If it's an Italian-made Bianchi, you may find a sticker saying "Columbus". Any of these would be worth upgrading, if indeed it needs upgrading at all.
You could likely upgrade derailleurs, hubs and rims, possibly brake calipers, saddle. Most modern derailleurs, although made for index systems, will work just fine if this bike has downtube friction shifters.
Hope you can post some pics of the whole bike from the drive side!
~Sherry.
All vintage, all the time.
Falcon Black Diamond
Gitane Tour de France
Kuwahara Sierra Grande MTB
Bianchi Super Grizzly MTB