Is there enough meat on this carb casting to drill & tap for replaceable idle air bleeds, especially on the primaries?
I don't know what the thread size is for the available jets, but I could make my own with 6-32 or 8-32 brass set screws.
thanks.

lots of good info herehttps://www.tapatalk.com/groups/racingfuelsystems/index.php:

Use a nice sharp drill bit with a decent amount of pressure about .093-..098. The bit will grab and pull it up out. The hole will be too big for 6/32. The problem will be sneaking the tap handle past the air horn. You might as well machine the air horn off.

They make tap extensions and even extra long taps.

Heck, you probably have some 8 point sockets that you could use to run a tap in your tool box.

those type of castings should be tapped with a form tap.
these kind of taps require larger hole sizes than cut [normal type] taps.
using a form tap will make stronger threads in that type of casting.

I used a spiral tap, very easy to do.