I know what they are factory set at but I always heard you take them down .005 for every 75-100 hp you pick up. So, I am wondering if this is true and if so what should I set my plugs at? I am sitting at about 410-420hp

 

With your compression, I would try at least .040. Maybe .045.

Get a hotter coil and have no worries.

 

Ill try that and see if I can fix my miss. Anyone else want to chime in?

 

Combination Motorsports told me to run my plugs at .040 for my NA setup. I would run somewhere around this.

Brandon

 

Sounds good, I will adjust accordingly.

 

.035