The reason you're not getting much feedback is that you have a tendency to ignore good advice and make up excuses why things some of us have seen and fixed for probably longer than you've been alive can't be happening. When that happens most of us oldtimers just sit back and watch you struggle. Some folks learn by listening, others learn by watching, and a few people just gotta pee on the electric fence and learn the hard way.
Those plugs are fuel fouled. The rough running and fuel stains on the intake manifold confirm it. Yes, you need a good carburetor rebuild, and that needs to include a long soak of all the metal pieces in a strong dip cleaner, followed by a thorough HOT water rinse and a ridiculous volume of air blown through all the passages with a high pressure air nozzle with a needle-point tip on it. Soaking and rinsing softens the crud, then the air blows it away. There are no shortcuts to getting a carburetor clean, and the stuff in the spray cans isn't sufficient to do that. Follow the instructions in the rebuild kit to the letter- - - - -they're not suggestions. The Rochester 2 barrel has a power valve- - - - -it's under the long spring-loaded plunger that's in the top assembly. Be very sure the power valve plunger works freely and the check valve it moves is completely free of gunk and varnish. When manifold vacuum is low, the plunger forces the valve open and gasoline bypasses the main jets. A stuck plunger or power valve guarantees a too-rich mixture all the time.
Have you made and installed a starter heat shield yet?
Jerry
