Jerry, I believe we're getting close and like you say there may be more than one thing.

I had to think on it a while, for it all to settle in. Remember, we're getting information in bits and pieces so it's hard to keep it all in order, not like we're there doing it.

Black sooted up carb, #1 & 3 plugs fowled, popping in exhaust and intake.

He needs to go back to cylinders 1 & 3 and compression test again. This has all the classic signs of a head gasket starting to leak between cylinders 1 & 3.