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Old 05-01-2008, 08:28 AM   #1
jugernot
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Is there a site that will help me determine the needed plug gap?

My 327 Engine

327 Large Journal Block .40 over
Edelbrock Proformer RPM cam and intake
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World Torquer Heads
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67cc combustion chamber
3/8 studs
Comp Cam roller tip rockers and lifters
MSD Distributor
MSD 6AL electronic ign
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Old 05-01-2008, 08:41 AM   #2
El Jay
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Re: Is there a site that will help me determine the needed plug gap?

Nice truck

Don't have any particular site info, but all the manuals sitting here next to me say it should be .045".

Hope that helps.
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Last edited by El Jay; 05-01-2008 at 08:41 AM. Reason: spelling
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Old 05-01-2008, 09:37 AM   #3
Wreckless_71
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Re: Is there a site that will help me determine the needed plug gap?

Anything with HEI is gonna have .035 - .040, pretty much the standard...
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Old 05-01-2008, 12:58 PM   #4
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Re: Is there a site that will help me determine the needed plug gap?

Since you have an MSD box in the mix, gap requirements are probably different from stock. Your best bet is to go to www.msdiginition.com and search the forums there.

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Old 05-01-2008, 06:55 PM   #5
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Re: Is there a site that will help me determine the needed plug gap?

thanks for the input.
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Old 05-01-2008, 08:28 PM   #6
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Re: Is there a site that will help me determine the needed plug gap?

I think it's .060 when you are running a 6AL box.
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Old 05-01-2008, 11:47 PM   #7
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Re: Is there a site that will help me determine the needed plug gap?

.035" for points ignition
.045" for GM HEI electronic ignition

Whatever the manufacturer recommends for any other ignition. Check your MSD literature.
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Old 05-02-2008, 01:00 AM   #8
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Re: Is there a site that will help me determine the needed plug gap?

If it is a driver, I would go a little conservitive on the gap too. Making more gap will wear out components quicker. So if MSD says .045 to .050.. I would go for the .045 personally.
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Old 05-02-2008, 02:10 AM   #9
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Re: Is there a site that will help me determine the needed plug gap?

jugernot- I'd like to know this information if you do find it.
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Old 05-02-2008, 04:37 PM   #10
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Re: Is there a site that will help me determine the needed plug gap?

I called MSD yesterday and well I will say they were not very helpful. When I asked what gap should I use. The response I got was "Well what is the recomended gap for your engine. I said I think it is between .035 and .045. Response "well why not set it for about .040." It sounded like he was guessing and did not have a researched answer.

I was a little disapointed, because the amount of money you spend buying a so called quality part, they should have a better tech department for consumer questions.
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Old 05-02-2008, 04:43 PM   #11
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Re: Is there a site that will help me determine the needed plug gap?

With my Bigblock motor I used Delco R45TS plugs running a 6AL box, and gapped them .040 with no problems.
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Old 05-02-2008, 05:56 PM   #12
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Re: Is there a site that will help me determine the needed plug gap?

I have no idea where .060 came from but that is way to wide...
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Old 05-02-2008, 07:08 PM   #13
El Jay
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Re: Is there a site that will help me determine the needed plug gap?

Quote:
Originally Posted by Wreckless_71 View Post
I have no idea where .060 came from but that is way to wide...
Early GM HEI's ('75-76 era) called for .060" when running R44TX plugs.
They revised it to .045" with R44T plugs.

So that is where I'd guess the .060" came from
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"Ah women. They make the highs higher and the lows more frequent." Friedrich Nietzsche

"Never kick a fresh turd on a hot day." Harry S. Truman

GUN CONTROL: Never having to say, "I missed you."

Always fire two warning shots into your attacker's chest area before putting a bullet between his eyes. Paraphrased from Louis Awerbuck
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Old 05-02-2008, 07:16 PM   #14
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Re: Is there a site that will help me determine the needed plug gap?

Quote:
Originally Posted by El Jay View Post
Early GM HEI's ('75-76 era) called for .060" when running R44TX plugs.
They revised it to .045" with R44T plugs.

So that is where I'd guess the .060" came from
Aren't those for a colder heat range too?
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Old 05-02-2008, 07:31 PM   #15
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Re: Is there a site that will help me determine the needed plug gap?

Quote:
Originally Posted by Wreckless_71 View Post
I have no idea where .060 came from but that is way to wide...
The directions for the 6AL box have a chart for plug gap. It lists, up to 10.5:1 compression-.050-.060.

It's on page three here-
http://www.msdignition.com/pdf/6%20series/6series.pdf
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Last edited by powell72; 05-03-2008 at 04:58 AM.
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