'66 273 BBD Carb

Hello:

I broke one air mixture screw off in the carb when trying to remove it. Half of the screw is still in the carb throttle plate. Apparently, the mixture screws are not meant to be removed.

There are threaded holes that angle down toward the screw, maybe holding the air screw in?

There doesn't seem to be a way to remove whatever is in the angled holes though, either.
This is an original California carb, which may be why the screws can't be removed.

Any advice, short of "new carb?" :(
Thx