Can running rich cause the oil on the cylinder walls to get onto the spark plugs? My plugs have what appears to be light oil deposits, and smell like fuel. I dont see how my valve seals could be bad since my heads are almost new, and the entire bottom end came out of a good running car. If something's wrong with this engine I quit....

 

I would have to say that the motor is running too rich, and is probably unburned gas on the plugs.