Snake Oil!

Another oil change is in plans. This is a quick synopsis of events:

Add half a can of seafoam to crank case and ran half through the intake.
Drove it about 20 miles and changed the oil. It was nasty and black as night.
Added 5 quarts and and another half can to crankcase and ran another half can through the intake.
Put about another 25 miles on it. Oil change tonight. I'm sure it's just as you described. Blech!!

I'll probably run this oil for about 50-100 miles until I change it again. I'll keep an eye on it.