I know, this topic has been covered numerous times, but I haven't been able to pull up any searches.

45k miles and numerous mods later, I guess it's a good time to replace the plugs and maybe the wires. My question is, should I go with the NGK TR55 Spark Plugs, Stock heat range, gapped at .050, the NGK TR55-IX Iridium Spark Plugs, Stock heat range, gapped at .050, or something a bit colder? Also, I've never seen a definate yes for upgrading wires. Any change in that?

 

I run the 55s gapped at .052 with good results. On the wires, the stock carbon cores are good till they start to degrade. Depending on how many miles you have on you stockers, it may be a good investmemt. I have Magnacores but they are pricey and I didnt notice much of a difference with them. You may want to try some MSD or Taylor wires.

 

You DON'T want to go a heat range colder on the plugs. With aluminum heads you dissipate a ton of heat out of the combustion chamber. Add to that the colder thermostat you're running, and going a heat range colder will hurt your performance.

 

I haven't had any luck swapping plugs on any of my vehicles, but *BY FAR* the best improvement in driveability vs price, was the addition of better spark plug wires.

When I tossed in my MSD's... it was like night and day with lowend power. Quicker throttle responce, easier to cruise at lower throttle openings, cleaner 'pull' from down low.

I see now the Silverado SS comes with "low resistance plug wires". Heh.