Thread: spark plug gaps

what would be a good gap to gap autolite copper 606 to on a completely stock car

thats what i thought but i figured i better ask plus i didnt know if it be better to go wider so i thought id ask. (i have no owners manual)

Originally Posted by archemedes

.060 is recommended by GM isn't it?

Yes you are correct

thanks everyone for the quick response got r done.

well i wewnt with .060 thats what i thought it was so thats with that here in the next month or so ill be getting colder plugs.

Originally Posted by Toasty

but the car didnt come stock with standard copper plugs, so the gap could be different.

Doesn't really matter. When you look at enough plug manufactures the .060 or at the very least .059 is recommended. Gaps only tighten up from there based on additional boost (smaller pulley, turbo, nitrous etc) mainly to prevent spark blowout. The only time I've seen a smaller gap recommend versus whatever gap you normally run, mods being equal, is in the side gapped plug write up.

fwiw although Autolites are copper core, that doesn't mean the center electrode is copper on the outside. Unlike the iridium and platinum which has a light coating on the outside. Only the Brisk and Nology appear to have solid silver center electrodes.