If Campagnolo had an embarrassing secret vice, it was its love for single pulley derailleurs. This despicable dalliance started with the 1953 Campagnolo Sport, continued with this, the 1963(?) Campagnolo Nuovo Sport, and was raging, unabated, as late as 1968, when the Campagnolo Sport Extra was still featuring in the catalogue. Surely someone should have taken Tullio Campagnolo aside and told him to get a grip on himself.
These derailleurs pandered to the fear amongst some cyclists that the extra friction of a second pulley wheel would hold them back. Everything that makes a good derailleur was sacrificed in order to avoid this dastardly friction.
In terms of gear changing (surely an important aspect of a derailleur) these models were about as much use as a chocolate fireguard. I once spent a whole afternoon trying to get a Campagnolo Sport to change reasonably across an undemanding mid range freewheel - to no avail. After this marathon session, it took only five minutes to remove it and fit and adjust a SunTour. Make no mistake, the single pulley derailleur deserved no place in the world after about 1948, let alone in 1963.
Dig the groovy curve on that pulley cage, though - very Ninja.