440 plugs

Bewy said

NGK 4 heat range......unless the engine will be at max rpm for minutes & not seconds, then use 5s.

Although is an extreme case, this engine lost 1/3 of it's hp with plugs that were too cold.....

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I've always liked how ngks ran in my 2 stroke bikes, never had them in an old car before ha. how do you determine the heat range? i've seen alot of people recommend

BKR5EIX-11 Spark Plug - 5464​

would these be 5 heat range? and the lower the number the hotter correct?