Spark Plug Heat Range

[XfireZ51]

Originally Posted by flyin ryan

oh...i would go a touch colder, one heat range, that's all. porting is one thing but compression & cams ( cam timing ) are another & i'm assuming you haven't messed with that? plug gap wise i'd stay around .035" to .040". nothing to be had there, except the more gap you have the more it taxes the entire electrical system, wires, coils etc.

FR,

That's what I am planning of doing is go a heat range colder. What would be the equivalent of a 41-601 or 41-600?