Indy Big block, take the NGK plug out of the box and put it in the head. I think they are .030" ish... I don't bother to check them.  Feel free to try whatever gap you want, but if you're not having an issue w/ the spark blowing out due to high cylinder pressure...I don't think you're gonna see a difference.
CHIP
'70 hemicuda, 575" Hemi, 727, Dana 60
'69 road runner, 440-6, 18 spline 4 speed, Dana 60
'71 Demon, 340, low gear 904, 8.75
'73 Chrysler New Yorker, 440, 727, 8.75
'90 Chevy 454SS Silverado, 476" BBC, TH400, 14 bolt
'06 GMC 2500HD LBZ Duramax
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