Harmonic balancer blues...

[DirtDonk]

Sooty could potentially be from weak ifnition. But it could also be from other normal things, such as a choke staying closed longer than it needs to, or the carburetor running a little rich, or the PCV valve not working properly.
Among a host of other things I suppose.

 

[Broncobowsher]

1,4,5,7 all share a single barrel on the carburator. You have a carburator issue. Half of your carburator is running super rich to leave the fluffy carbon on it. This is not a little adjustment of the idle mix screws issue. You have a clogged air bleed type of issue.

Pull the carb, do a proper rebuild, make sure ALL the passes on both sides are free and clear.

 

[DirtDonk]

Check to make sure the Jets are the same on both sides.
Check to make sure the PCV valve is plumbed into a common Plenum area and working properly.
Checking for vacuum leaks is never bad idea.

 

[Blitzen72]

Update...

Tore apart the carb (old Holley 4412-3) and thoroughly cleaned and rebuilt it tonight. Had a 6.5" power valve, dropped down to a 4.5" power valve. Initially set both of the idle screws at 1 turn from tight. Put her all back together, fired right up, at about twice the idle she had prior to. Lowered idle way down, cleaned all 8 plugs, will find out this weekend if this took care of my plug fouling issue.

 

[Blitzen72]

She 'seems' to have better power - time will tell....