A left and drill bit in prep for an easy out will likely remove it. But the metal shavings need to be nowhere near the engine. You might as well tear it apart for a cleaning and rebuild kit at the same time.
That’s the IF. Unless the shafts are worn, or it needs upgraded to a 4bbl, it’s a good excuse, but not a good reason. @Primer66 has some good info to decide where to spend his/her money now.
This is the biggest I’d put on a street-able 302/289. If it is a straight six, we need to look elsewhere for a different carb. It will not ever useful 650 CFM, but the adjustable flap and new style venturis should be a good fit.
I am struggling with a Holly 600, if I needed to put real effort into working on it U would be ordering the edelbrock tonight. As it is I am trying a couple more things before the holly goes.
Thinking about a Weber Down-draft set-up with 3 carbs if such a thing can be found.....
In case anyone stumbles by this in the future - remove the top plate of the carb (6 screws or so) and access the stud from the bottom. I was able to grab it with pliers and thread it out.