5.7 crusader classic 2009

[Ryano]

Question on spark plugs .replacing Ac Delco 41-993 which were original to engine. They come pre gapped at.60. Box says not to change gap.. specs are to gap plugs at .45. Suggestions??
Thanks
Ryan

[a64pilot]

I’d gap them to specs.
Most modern ignition systems are so high energy that they could fire a rusty nail.
What’s written on the spark plug box is very generic, the engines’ specs in my opinion take precedence, however be sure you gap then correctly, it’s actually pretty easy to damage a plug closing up the gap by hitting it with a wrench etc. and I assume is why they say that on the box.
I would also use some silicone grease on the boot, and anti seize on the plug, but be careful with the anti seize, leave the last two threads dry because some anti seize can actually short a plug as it has metal in it.

[Ryano]

Thank you for reply.