Gap For Autolite 25

THEUNDERCOATER

Active User
Aug 3, 2015
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Southern Maine
ive seen others say and my book days .50 gap for autolite 25 on "stock" 91 5.0 motor. Just pulled first two plugs out and they we're gapped at .46/.47

Thoughts?
 
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Mustang5L5

i'm familiar with penetration
Mod Dude
Feb 18, 2001
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Massachusetts
0.045" is the quotes gap for the older Fox Mustangs. 79-84 IIRC. I've seen a lot of sources carry that gap up to 1993 despite the gap on the later cars being spec'ed at 0.054"
 

Moosee1955

Active Member
Sep 30, 2016
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It's probably just me but I never had any luck with Autolites and 5,0 motors . A while back I had an 82 5.0 that I threw autolites in. Ran so crappy, 2 days later put in Motorcraft plugs gapped at about .054, ran great. Smooth, all my lost power came back. Just my two cents.


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89gtsleeper

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May 20, 2016
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As others have mentioned, stock spec is .054. As long as you are not blowing out spark, the bigger the gap, the stronger the spark. If you close your gap in to .045, you are essentially producing a weaker spark. But again, if you are using a stock motor, the difference between these will be minimal. On a boosted car, the gap is much smaller.