You have a '26-27 carb with the swivel adjuster on top. But - the sleeve is missing that goes over the four-way box with nubs. A rod goes through the firewall and into that sleeve. It is shouldered so that it can turn the swivel. The rod you show is for the pre-1926 carbs (Holley NH, Kingston, etc.), You can order a new swivel sleeve and bend the ears over the swivel box. All is not lost, although you now have a pig sticker rod that can't be used with this carb - unless you install a swivel from an earlier style carb. Nah! 'Cheaper and easier to just add a new swivel sleeve.
Marshall