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What is involved in cutting back the spark plugs? How much can you cut back and what are the gains and drawbacks? Thanks in advance for any replies. :flag
My technique is on my site.
My time slips show a consistent and real 1mph gain in trap speed (i.e. 10hp). The only draw back I can think of is that it likely shortens spark plug service life. I just regapped the cut-back plugs in my IROC[ after over 1yr of service they had opened up from .045" to .050".