spark plugs

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Dec 1, 2010 | 02:31 PM

#31

aking225

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From: Western mass

and they did put they were fuel injected ni 87

Dec 1, 2010 | 08:15 PM

#32

skyfox10

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From: southwest michigan

302 f150 spark plugs (autolite 25) would be 14mm thread. Explorer 302 (gt40/gt40p heads) spark plugs (Autolite 764 & 104) are still 14 mm thread, this still doesn't make sense.

Dec 1, 2010 | 08:28 PM

#33

aking225

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From: Western mass

according to the previous owner the motor was out of a 81-86 mustang, that was the problem, any idea on how much power thats making?

Dec 1, 2010 | 11:37 PM

#34

John D in CT

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Joined: Dec 2010

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Study the threads on the old plugs really carefully; see if they've picked up any material from the heads from previous cross-threading, or corrosion. A 24-yr-old engine has seen a lot of plug changes, and it's possible that the old plugs with with messed-up threads will fit nicely into messed-up spark plug holes where the new ones won't.

Then study the threads on the new plugs, especially right where they start. Make sure you didn't get a bad batch. It happens, but it's pretty doubtful. I wouldn't even mention it if not for the fact that this problem makes no freaking sense.

Finally, study the threads in the head as best you can. They might be really screwed up, or just slightly screwed up. If they're only slightly screwed up, you might just need to run a spark plug tap in and out of each one. Load the tap up with a good coating of grease and the amount of filings that work their way into the cylinders will be miniscule.

Please let us know how this problem gets resolved.

Dec 2, 2010 | 05:29 AM

#35

aking225

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From: Western mass

the problem was that it was out of an 81-86 mustang, and the heads are diffrent, i got new plugs and they went right in

Dec 4, 2010 | 10:19 AM

#36

skyfox10

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From: southwest michigan

I still don't understand. those mustangs, if they had a carb, were still using autolite 25's. The fuel injected models used autolite 26's. I still don't understand how this would cause a problem. What spark plugs did they give you that fit correctly?