You don't want to use a shorter plug than stock on the Zetec. It's said if you use a shorter plug the cylider might not seal properly and it would be bad in the long run. I used to run a shorter plug then found out it was shorter and switched to the Motorcraft AZFS22Cs. They are the only plug I've found over the counter that fit perfectly. Copper and one step colder is perfect for a 50shot.
2000 Rio Red I4 Cougar
200whp & 210wtq at 9psi
254whp & 276wtq with NX 35shot
WRX TD04 Turbo, Cut Short Shifter, Strut Tower Bar, 17" ZN Wheels, Roush Springs, Starion Intercooler, NX 35 shot, HKS SS BOV, Full 3" exhaust,StreetFlight Chip
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