Spark plug
pedant
Joined: Jan 2008
Posts: 23,576
Likes: 40
From: EXTREME southwest CT
I don't think the 351C was ever installed in a truck.
351M, from '80-'82 maybe?
Duraspark II ignitions called for .044" gap.
This should be shown on the sticker affixed to the radiator support.
351M, from '80-'82 maybe?
Duraspark II ignitions called for .044" gap.
This should be shown on the sticker affixed to the radiator support.
FTE Legend
Joined: Nov 2015
Posts: 30,941
Likes: 4,126
From: Angier, NC
Just know the wider the gap the harder the box has to work to push the spark across it and could lead to the box failing.
Remember when HEI first came out the gap was .060? The modules would burn out so they closed the gap to .40-.045 I think it is.
Dave ----
Remember when HEI first came out the gap was .060? The modules would burn out so they closed the gap to .40-.045 I think it is.
Dave ----
pedant
Joined: Jan 2008
Posts: 23,576
Likes: 40
From: EXTREME southwest CT
I'm on my phone, so I don't see signatures or much identifying personal information.
Sorry about that.
pedant
Joined: Jan 2008
Posts: 23,576
Likes: 40
From: EXTREME southwest CT
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Posting Guru
Joined: Jul 2015
Posts: 2,239
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From: Northeast Ohio USA
.40 to .45 gap will cause less stress on the module.
IMO, NGK are not the best plugs to use as they are a "high fire" plug traditionaly used in Asian built engines. I personally would try to source OEM Motorcraft plugs. And the nay-sayers chime in....3....2....1...
IMO, NGK are not the best plugs to use as they are a "high fire" plug traditionaly used in Asian built engines. I personally would try to source OEM Motorcraft plugs. And the nay-sayers chime in....3....2....1...
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Posting Guru
Joined: Jul 2015
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From: Northeast Ohio USA
BTW.....What constitutes a "bad plug out of the box" ?
FTE Legend
Joined: Nov 2015
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From: Angier, NC
Dave ----
pedant
Joined: Jan 2008
Posts: 23,576
Likes: 40
From: EXTREME southwest CT
Bodies that are not crimped tight on the insulators, electrodes that are not sheared clean or square.
It's a sparkplug.
I don't want to have to pack up and go to the parts store to grab another one because of your complete lack of QC.
What is "high fire"???
Maybe I'm just too old to know these things.
It's a sparkplug.
I don't want to have to pack up and go to the parts store to grab another one because of your complete lack of QC.
What is "high fire"???
Maybe I'm just too old to know these things.
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OrangeJuice
335 Series- 5.8/351M, 6.6/400, 351 Cleveland
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Apr 21, 2019 09:20 PM
dustinleavitt2000
335 Series- 5.8/351M, 6.6/400, 351 Cleveland
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Jun 15, 2003 05:29 AM