I do not recognize that as a a known (to me) Bianchi serial number format. There are several ways in which it could be reverse engineered, with the most likely being a 1975, 1985 or 1995 model being manufactured in late 1974, 1984 or 1994. Photographs may aid in the identification, though that may be complicated if you are not located in North America, as most members are American based and Bianchi models and sources often varied by region. Ignore the forum warnings that you cannot post photographs until you have reached 10 posts. The photographs will be deposited in gallery album where members can view them.