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My 89 vette’s service manual says to gap plugs to 0.035 but when looking at plugs I’m seeing a range of recommended gap up to 0.045 so with stock aluminum heads what’s suggested?
2020 Corvette of the Year Finalist (appearance mods)
C4 of Year Winner (appearance mods) 2019
Anything in the .035"-.045" range would work. Typically, the manufacturer pre-gaps plugs what works best for the plugs. A variance of .010" slightly retards or advances electronic timing. For an '89 with an OEM LTR TPI, I'd lean toward .035 because low-mid performance (timing) gets you the most bang-for-the-buck. FWIW, I also thought the OEM cam was retarded (or had 2-deg lag built in....probabably to spread the power band and/or to increase VE. .045 would likely move the powerband a HAIR upward.
Really...after buying any [acceptable] set just make sure none of them are significantly different than the rest...and go with it.
I really should have said I was going to use AC Delco Plugs 41-808, double platinum’s. I installed a TPIS Super L98 cam but haven’t fired it up yet. Soon…🤞🏻
Here’s one of the parts sites recommending 0.045 gap for aluminum heads & specific to my vehicle.
Last edited by Cornhusker; May 24, 2022 at 09:37 PM.
Spark Plug Gap?
