I went to buy new plugs for my LS1 and they come pre-gapped at .40 and said to leave the gap there, instead of 60 how they were gapped when I bought the car.

Anybody know the rhyme or reason behind this??

 

New plugs have an iridium tip, and can be easily broken if gapped with a ramp style tool. 40 is fine.

 

Yeah...the reason they said not to re-gap it is......THEY DON'T WANT YOU TO **** IT UP!

 

There was a TSB regarding the plug change a few years ago. Search on Yahoo! for LS1 spark plug TSB or something along those lines and you should be able to find a .pdf document with the details.

 

That TSB was in relation to spark knock on take off. It said changing form platinum to iridium plugs could improve this.

 

Thanks! I got the print out from the dealer. I just thought it was odd but I haven't kept up with plugs as of late. My LS1 has 44k miles and the original plugs with many track runs and with the way I drive it, the plugs are probably gapped at 70. Time to change.

 

My original plugs were still gapped at 58, after all those runs and miles. The platinums held up pretty good. The new plugs definitely run smoother. GM obviously found a better plug for normally aspirated LS1's without head work etc.

The boots on the MSD wires are a little longer and putting the metal heat shields on the MSD's causes too much tension on the wires which could cause them to pop off. One of mine did. We removed all the metal heat shields and the wires fit perfectly.