Sounds like you are running rich. Soot in the tail pipe AND on the spark plugs means mixture is off... not 'flooding the motor' off, but enough to stumble off idle when you switch from the idle circuit to the high speed jets.
Personally I think your carb is off. I'd spend an hour or two with a vacuum gauge and a timing light to ensure that everything is set properly. Since nothing is wet the fuel pump isn't over pressuring the carb and flooding it, and that also means that the fuel pump is working. You have a glass pulsator dome so if you had a ripped diagram you could see fuel level go down.
If anything you will have a brandy new fuel system!
