EdH, thanks, this really helps alot. I read that post - wonder if that guy hangs around here somewhere. His post basically confirms alot of what I've already done.
That fitting is made out of "pot" mettle. Same stuff GM engineering was on when they designed the thing....
One dealer I called says he stocks a steel one but was out right now... the other said its just whatever GM sends and did not know about a steel version so now I'm not so sure there actually is a steel version (why would there be two versions anyway.) I'll take my magnet with me to check cause the so called pot version is of course non-magnetic.
Anyway, here's my experience so far: when I got the connector pulled away, I was left with the remainder of the fitting down in the hole. Oh joy, another great challenge in my life......but great minds think alike - like the post you found from "Jimb", you just get a hack saw blade - I used one from my saws-all so it was already narrow enough. I have a handle that accepts the saws-all blades. (I would not recommend using a freakin saws-all on the engine at this point). Feeling like Dr. Kildair, I carefully cut down parallel in three places just level across the very tops of the manifold threads. This enabled me to then carefully pry the pieces out. Except they fell into the hole.

But I have some of those little computer keyboard vac accessories that work on the shopvac so I can get into the hole and suck out the pieces which are just sitting down there. I also will shove the hose in there and, with the block plug pulled, will attempt to flush the block straight down through the engine. Have no idea what path it will take but I will also strain whatever comes out to check for debris.
As soon as I get the part I'll be able to go to specialty hardware store and measure the thread count (pitch if metric). Most of the engine is metric but hey its GM engineering.
Next I'll try to clean the threads with a tap or thread routing tool of some kind. Worse case is that the threads get too damaged to hold new part. If so, I'll need to go to oversizing and retrofitting a brass fitting or something. I wonder if there is some electrolysis issue that led them to use the pot metal. If I use something conductive, it may cause a problem???

Or maybe they used that because its so close to the hot wire of the alternator and too many mechanics were shorting out when they detached the hot lead and it rested right on this fitting.....Merlin, are you around here somewhere?
So, as soon as I get the other car back from wifey, I can go find the parts and I'll post the thread count etc.
Thanks for the help.