Originally Posted by T-Mar

The rear derailleur is the entry level Campagnolo Valentino Extra. Assuming it is OEM, the bicycle is no older than the 1969 model year. I don't know the Bianchi model name during this era but for the 1971 model tear it was called the Rekord 71, then it got another upgrade in 1974 and was rechristened Record 74. so it's tempting to call it a Rekord 69. Regardless, given the Valentino Extra and seat post collar, it should be 1969-1970.