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What should my Spark Plug Gap be at?

23K views 18 replies 8 participants last post by  91sleeper  
#1 ·
hey guys, i bought some Autolite 25 Spark Plugs, and i checked the gap on them and they are about .044. I though that was a little much, i though i saw some of you saying on other threads that you guys run .025-.035? Is that correct?

Im about to install them and was just wondering if i should re-gap them? Seems high to me, so im hoping you could help me out.

My motor isnt stock it has the following mods ( hopefully this helps a little )

-302 block - Bored to a 306.
-Roush/World industry 200cc Running intake Heads with 64cc Combustion chambers ( but doesnt flow as well as they should.)
-F-303 Cam
-75mm TB
-190LPH Fuel Pump with adjustable fuel regulators
-Full MSD ignition
-Underdrive pullies
-Trick Flow track heat Upper/Lower Intake

I dunno if it makes a difference but those are some of the mods, not crazy but not stock, so i dont know if it makes a difference in the spark plug gap. Just wondering what i should re-gap them too or if i should just leave them alone.

My old Accel spark plugs that i just took out were gaped at about .035 with 8mm Wires and i just bought new 8.8mm wires just trying to figure out what gap i should go with and what would work best. Thanks for the help guys! - Joe.
 
#3 ·
Well im no mustang guru im sure everyone here knows this heh. I just got it as a project and to learn from, but ive never had to replace spark plugs and i dunno if it matters the gap, if its better to have the gap closer. And if so what i should run them at.

And suggestions on what the gap should be? Just seems a light high to me for a non stock motor, but then again im asking you guys b/c you know and i dont so whatever you guys say i a great help. Thanks. - Joe.
 
#7 ·
Ok thanks!

Yeah the only reason why i was wondering about the Gap or maybe Re-gaping them was b/c the old Accel ones were gaped at .035 and these are gaped at .044 and that seemed like quite a difference to me, so what why i was a little worried and wondering.

But you guys say i should have nothing to worry about and just throw them it at the gap they are now at .044? Or Re-gap them, and to what should i re-gap them too?

Sorry just want to make sure i have this clear before i go in there and put them in. Thanks guy for all the help and advice! Really appreciate it! - Joe.
 
#9 ·
i though i saw some of you saying on other threads that you guys run .025-.035? Is that correct?
That's for boost. Bigger gap equals better spark, as long as the ignition system is powerful enough. Your engine is around stock compression, so i'd think 0.044"-0.05" is fine.