I'VE GOT THE POWER!
I didn't wake up the neighbors, but after my ride today, I checked the valves and springs, warmed it up and rechecked the timing. All good. I even went by the parts store and picked up an old school condenser and points just in case, I wanted a set anyway. I took off for a test drive, and now I'm back to terrorizing the roads. Bwahahaha!
I don't know what I did, sometimes messing with too many things all at once is not a good way to find out what the problem is. The only significant thing I did was clean the plugs. It could be some intermittent ignition thing, oh happy day. Well if it happens again, I'll drop the regular points and condenser in and go from there.
It still stumbles some around 2500rpms. I need to either learn this carb thing or find a local weber whisperer.
Sooty black plugs not good. 65 idles might be a little rich. My car also stumbles like yours, engine builder told me the venturis in the 44s are a little too big. He said if I went down one size it would fix the stumble but cost 3 or 4 hp. I'm gonna live with it. Your engine is a lot bigger than mine so maybe the venturi size is good for your engine. Just a guess. Bruce (air cooled) had the same stumble as mine and changed for the smaller Venturi and fixed it. Both ours are 2110s though.