Is it "wet" oil or does it resemble carbon? Do you think the oil ran down the threads from the plug well and wet up the plugs as you were removing them? Usually plugs wet with oil means the rings are worn. Valve stem seals and guides will usually burn up and leave puffy oil deposits. Have someone ride behind you as an observer. Get on the gas then let off on it suddenly. If smoke comes out when gassing it, it's the rings. If it smokes when off, it's the valve stem or seals. Vacuum is high when off the throttle so the engine sucks the oil from the guides.
