I'm about to change my plugs and I got some NGK 55's. When I checked the gap its at 0.055, this is too big for my pretty stock LT1. How can I make the gap smaller, or will I ruin the plugs?

 

I believe the recommended gap is .050. It takes very little to tighten the gap on the plugs. Just a little tap will do: then regap if necessary. You can pick up a cheapie gapper that will also narrow the gap for you. Don't forget your anti-sieze.

 

will the 0.055 gap hurt any performance over the 0.050 gap?

 

No. But it isn't hard to change the gap. Plus, if you gap all of them, you can make sure they all have the same gap. Just tap it a few times with the gapper, then regap them. You won't hurt anything.

Benji

 

just remember the plugs we use are not only for our cars so you really need to re-gap them for your application.

 

Thanks for the help guys, I closed up the gap and regapped them to spec as you said.

 

Where are you guys buying plugs?

It's been many years since I've bought plugs that weren't pre-gapped for the specific application.

 

Well a lot of them say pre-gapped... and they are... just not to our specifications In other words, I think they shoot for a gap that will work in many applications, hence your 5/1000ths variance. Don't ever instlal plugs these days without checking the gap. Most the time, you'll have to gap them. Might as well get comfortable with it.

You didn't close the gap all the way did you? Just close it a bit or open it a bit until you've got it set right.