I was told that it is the additives from the oil and not to worry about it. The crud in the photos above came from Brad Penn oil and was not soluble with mineral spirits. The mineral spirits just moved it around but the pan cleaned easily.

The only thing in my engine that is black is the spacers between the T&D rockers and they looked perfect when inspected. Also the engine was clean and everything looked great. It's ran great all summer, I did change to Driven oil.