The plugs are Ford part #SP-519/CYFS-12Y GAP AT .053. Try standard plugs and you can feel the lost of power at high end.
Performance and dyno results are in past threads. Compare your number and see if there is a difference from mine.
The plugs are the only difference that I can tell between our white lables.
Last edited by John S. Murbach; 08-20-2013 at 10:31 AM.
Reason: spelling
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