Misfiring all of a Sudden

Happy Birthday RRR

Well, the spark plug is new and the wire set I bought brought eight so I put a new wire on there as well. New cap and rotor too.

Car ran good for about 10 miles and new it’s missing and fouling up again, plus black soot out exhaust.

I adjust the balances around 150 miles ago, maybe I should go back and readjust. Rather not mess with the carburetor.. what do you think? Could this be symptoms of incorrect valve lash on a single cylinder?