[Steeveedee]

Originally Posted by RichardJ

>>RustyPile, Before you pull the head, do ALL the "easy" stuff first. A leaking intake manifold gasket will produce the same "dead cylinder" symptom as a burned valve. <<

X2

Spray carb cleaner around base of carb and intake manifold.

A carb problem can cause it to blow black smoke, but you said you tried three carbs. I see too many wires. Loose that piece of crap pertronix. A really weak spark with those plugs may be giving you the smoke. Ignition Points are far more reliable, they just need more maintenance.

Those plugs are so grungy, it's hard to see what I'm looking for. The head does appear to have plugs for A.I.R. smog tubes, but that alone doesn't tell me it's a later head that uses tapered seat spark plugs. You should inspect the spark plug hole to see if it is supposed to have the earlier style gasketed spark plugs.

That's a good observation. I noticed a lot of slag(?) on plug #6's seat. Maybe it has the wrong plugs.

OP- Add a pic of the head where the plugs screw in, we can verify what plug type is proper.