What you should have done was took one of them dirt spark plugs and screwed it into you nice new head and took a picture.
instead of just showed us you different heat range spark plugs. The threads are the same length on both, screw one in and take a picture.
I took what 12many said as the truth when he said that the spark plugs didn't cover those threads.. so I looked at the spark plugs he used and compared it to the new spark plugs that I now use..
and kind of like you said I don't want to screw in old oily spark plug into my new heads... See how nice I answered...
