You called?

That's a great find. Are you sure they are 6 speed syncros? 6 clicks? Maybe they are 7 speed; not sure Campy ever had a 6 speed indexed shifter. Anyway, word on the street is that the syncro shifters performed horribly. As c_m_shooter suggests, put them in friction mode, or get another set of shifters. Try out the 8 speed cassette. If the derailleur or shifter doesn't have enough travel for 8 cogs, either don't use the largest cog or get a spacer and a 7 speed cassette.