I’m in the process of changing the spark plugs and wires on my SRT6. The plugs I’m using are Bosch’s double iridium 9603 spark plugs. They’re pre-gapped at .044mm but most not all of the literature I’ve read on the forum and elsewhere states owners have their plugs gapped at .039 some even less than that. My question is should I adjust these to a shorter gap or should I leave them to the Bosch spec? Thank you in advance for any insight into this.

 

I believe you mean .044" not .044mm. .044mm = .0017" which would be equivalent to almost no gap. I would go with .039" (1mm). Most of the time the manufacturer uses an arbitrary gap setting value as the plug is used for many different applications.