Originally posted by tallyrc
i may be way off but i was under the impression that you just about always want the hottest plug you can get for a .12 and adjust detonation with shims. ask motorman or dino or palmaris, they know everything.
Well as you can see by my last post, it isn't allways like that. You have to take into account WEATHER, and NITRO%, and NITRO% determines the right shimming of your engine.
As per OS Turbo plugs, they have three types rated by ambient Temp:
P6 for low temp applications
P7 for average all season use
P8 for high temp applications
AFM