spark plug gap?

[Patrick Kenny]

Dear Forum,

Greetings from Dublin. Any thoughts on what the spark plug gap should be for the Chrysler 400 in my 411(IV)? More generally, can anybody summarise the consequences of having the gap too small (large)?

Good wishes,

Pat

[herrbartlet]

Can't believe no one has the correct info for you. I only have spark plug data on the 360 (Champion RN12Y) and 383 (Champion J11Y) engines, both of which recommend a gap of 0.035"/0.9mm, so until someone posts a definitive answer, you'll not be far off using this gap.
There's plenty of info on the internet about using incorrect plugs and/or gaps, but at the end of the day, we are all trying to get our engines running as sweetly and efficiently as possible, which means the correct heat range plug and gap, as well as timing of course. You go away from optimum settings and you don't get optimum performance.

You could always try the 3 or 4 electrode plugs (more sparks/better combustion), if your wallet is sizeable enough, which have pre-set gaps.

[Geoff Kingston]

The 411 Handbook says .035 for the 383 engine and one of the Chrysler websites has the same gap for the 400 and 440 engine.