The Champion C57CX is Perfect...I'm sure if you cross that number over to the NGK you would have the Prefect Heat Range.And at 15.1 CR gap the plugs .022-.025 that will make a Big Improvement.

PS Sorry I mis-read you post that plug is for a 15-1 CR and I have never run a 11-1 CR on 93 octane before.Again Sorry for the mistake.

Last edited by MRMOPAR622; 05/17/14 08:03 PM.
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