I thought the 65-66 z-bar had a different lower rod attaching style. The 67 z-bar (what I have) has a hole in it for a pin on the lower rod to go through. The pictures of '66 rods I've seen have a hole in the end of the rod so a pin on the z-bar can go through it.
Check your z-bar, because obviously one rod isn't going to work on the other z-bar.