lets say I ran a plug one or two heat ranges higher than i was suposed to.What could happen?
no nitrous but its a high comp motor(almost 14:1)

 

could leave too much heat in the chamber and burn the plugs up. they could get so hot they could predetonate the charge.

Inspect them for detonation but for high compression motors you want a colder plug to keep chamber temps down


what plugs you running?

 

Ngk 5672a-8

 

thats a good plug for racing... you should be ok with it. I dont think your too far off heat range wise. other recommended ones would be 9 or 10 heat range rating.

for alot of street use and not high rpm racing, a hotter plug is better. keeps less fouling but on a race motor, it will get too hot. so colder is better

 

ok so since it is a race only motor and it does see over 7000 rpm I might change to the 10 heat range and see what happens