[MagicRat]

The clicking noise may be a carb backfire.
It sounds as if its running too lean when the secondaries open, which can cause a backfire. The lean condition is due to either dirt/gum in the fuel delivery passages for ther secondaries (most likely) or improper adjustment of the needles for the secondaries (less likely)

BTW If the secondaries did not open, the car would run fine, just a bit on the slow side.

I might suggest a carb rebuild and pay particular attention to cleaning up the float bowl and the needles and seats for the secondaries.
If you have not done this before, get a manual that covers Q-jets and get a rebuild kit. Carbs are easy to rebuild with the right instructions.