From what era was this freewheel hub? Campagnolo for a while during the late 70s up to the early 90s offered a Portacatena system, the normal version of the idea was to put a wheel with a 5 speed freewheel on a 126 frame, and the 'missing' cog space was filled in with the portacatena. Some manufacturers extended this to 6 speed (and arguably 7 speed) freewheels by building 130mm OLD frames and Campagnolo obliged them with the necessary axle and hub.

http://campyonlyguy.blogspot.com/201...rtacatena.html