Hey sky, to read your plugs, run it with N2O and then IMEDIATELY shut it down and pull every plug. It isn't hard to read them, you will easily be able to tell if you are running lean/have detonation .Dont just look at one or two. You can't hear detonation but how loud is it in that beast of yours? If you want to keep your engine, follow the reccomendations, 92 octane, back off your timing and dont hit it till 3000 rpms. One step colder plugs wouldn't hurt either.
Don't take chances with N2O...If you decide to go with a larger shot, make sure your clutch is up to it also!
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My Mustang
91 LX Conv. 52,000 orig mi. Hurst shifter,King Cobra clutch, 3.55 grs, NOS 150 kit, MSD 6al, MSD timing control, malory coil, pullies, adj fuel reg, BBK 70mm tb, Pro-m 75mm maf, battery in trunk, JBA: shorties,subs,strut tower brc, Comp eng. 6 point cage, dynomax 2 1/2" exhaust, Hotchkis lower cntrl arms, MAC cold air kit, off road h pipe. BFG 275/50/15 Drag radials