[vncj96]

Over the years I have read alot of talk about GM putting out a bulletin for the Vortec 5.7 going from a .060 to a .040 gap for the spark plugs. Yet when i search google or yahoo i cant find anything except what sends me back to this site. So, I need to put in new spark plugs on my beast and am wondering should Istick with the factory gap that the spark plugs are set to or adjust them to .040 as to what I have read alot of guys doing on this site. So what are REAL WORLD results form the gap change if any? Less hesitation, better MPG, longer or shorter spark plug life?????? Also, will adjusting these not so cheap spark plugs from a .060 to a .040 actaully cause premature wear on the spark plug itself.

 

[Caddiac]

I have no personal experience with changing the gap to .040. I have been running the standard .060 gap and the plugs look good after 100,000 miles. my guess would be that there would be a loss of performance if anything.