Can you try unscrewing the old one and see which way it unscrews?
It is Campy, yes. But it still could be British thread. I thought all Bianchis post late 70s or early 80s were British threaded... but I'm not certain.
Besides the length difference, apparently the bb cup faces are stamped 1.37x24 for English and 36x24 for Italian. I'll have a look and a measure tomorrow. Best to be sure. Don't want yet another ordering of the wrong part!
the bb cup faces are stamped 1.37x24 for British and 36x24 for Italian.