[Christ]

He may have been referring to "blow-by" which is a condition where rings don't seal, thus, combustion pressure blows into the crankcase, and oil gets sprayed up into the combustion chamber of other cylinders, which incorrectly describes your condition.

I presume that what's happening to you is that oil is getting on the upper part of the spark plug. You can verify a tube seal leak (upper seals or lower gaskets) by thoroughly cleaning all the tubes after pulling the plugs, cranking the engine over without the distributor plugged in to clear the cylinders of oil and whatever you put in to clean the tubes, then run it for awhile and swap the tubes with q-tips to check for oil before you remove the plugs.

Usually, you can also see evidence of oil leaking into the tube seals on the plug wires themselves, which have rubber sealing boots on them, and are about 3-4" long.