440 plugs

[NoahSewal]

I'm sure this has been beat to death on here but i'd like some of your guys opinions. Just a quick question about plugs for 440. Now that i've got my 440 way past the point of fouling plugs and it's tuned in well, would upgrading from autolite 85 give me better drivability/idle? i just ran with the 85s because they were cheap and i was fouling sets out when i was messing with carb sizes. mild iron head 440 with 6pack pistons and choppy .505 lift cam. Fbo ignition box and flamethrower coil. stock electronic distributor. i've read online that 85s would probably be comparable to the others with my setup but others are saying otherwise.

 

[Bewy]

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.....

 

[NoahSewal]

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.....

View attachment 1716292926

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?

 

[Bewy]

Yes, you are correct on both counts. The -11 is the gap in mm, 1.1mm or 0.044".