OK, a little heat and some PB blaster softened up the old cork. I used a small pick to get the material out. I got my dremel tool out with a very small ball burr and cut new slots into the needles and tried again. They just broke further down into the hole. The two machine shops I stopped by today wouldn't touch them. Time to dust off the home drill press.

Here is another question. What would happen if I drill out the broken needle then plug complete idle circuit so that the fuel cannot get to the slot or the hole where the needle jet was?

In theory, the center carb should have all the idle circuitry. I can see the outbords providing some idle mixture to avoid leaning out the cylinders furthest from the center carb. But having center carb doing full idle duty wouldn't be any different than having a 383 or 440 with a 2 bbl on it. Though the manifild desing on a dedicated 2bbl engine would be better suited for distribution.

Anyway. While we ponder that question, I will drill out and see if I can get a helicoil or keensert installed. I'll do it myself I guess.