CHAMPION PLUG HEAT RANGES
As mentioned about Champion plugs, lower # = lower heat range. Some other brands follow that pattern while others are lower # = higher heat range. Gotta check your brand.
FWIW N9Y were originally for high compression 340s and N10Y were for 426 Hemis. (I believe Champion 61 & lower were considered race plugs & didn't follow with the passenger car number sequence.)
As mentioned about Champion plugs, lower # = lower heat range. Some other brands follow that pattern while others are lower # = higher heat range. Gotta check your brand.
FWIW N9Y were originally for high compression 340s and N10Y were for 426 Hemis. (I believe Champion 61 & lower were considered race plugs & didn't follow with the passenger car number sequence.)
