Is there a site that will help me determine the needed plug gap? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

jugernot · 05-01-2008, 08:28 AM

My 327 Engine

327 Large Journal Block .40 over
Edelbrock Proformer RPM cam and intake
Edelbrock 600 cfm carb
World Torquer Heads
Manley Swirl polishied 2.02/1.60 valves
67cc combustion chamber
3/8 studs
Comp Cam roller tip rockers and lifters
MSD Distributor
MSD 6AL electronic ign

**El Jay** · 05-01-2008, 08:41 AM

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.

Wreckless_71 · 05-01-2008, 09:37 AM

Anything with HEI is gonna have .035 - .040, pretty much the standard...

HomerJ · 05-01-2008, 12:58 PM

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.

HomerJ

jugernot · 05-01-2008, 06:55 PM

thanks for the input.

powell72 · 05-01-2008, 08:28 PM

I think it's .060 when you are running a 6AL box.

Blazer1970 · 05-01-2008, 11:47 PM

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

Whatever the manufacturer recommends for any other ignition. Check your MSD literature.

Longhorn Man · 05-02-2008, 01:00 AM

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.

hotrodhomi · 05-02-2008, 02:10 AM

jugernot- I'd like to know this information if you do find it.

jugernot · 05-02-2008, 04:37 PM

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.

71Farmtruck · 05-02-2008, 04:43 PM

With my Bigblock motor I used Delco R45TS plugs running a 6AL box, and gapped them .040 with no problems.

Wreckless_71 · 05-02-2008, 05:56 PM

I have no idea where .060 came from but that is way to wide...

**El Jay** · 05-02-2008, 07:08 PM

Quote:

Originally Posted by Wreckless_71

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

71Farmtruck · 05-02-2008, 07:16 PM

Quote:

Originally Posted by El Jay

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?

powell72 · 05-02-2008, 07:31 PM

Quote:

Originally Posted by Wreckless_71

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

05-01-2008, 08:28 AM	#1
jugernot Life, Be In It..... Join Date: Oct 2003 Location: Novato, California Posts: 1,498	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 Edelbrock 600 cfm carb World Torquer Heads Manley Swirl polishied 2.02/1.60 valves 67cc combustion chamber 3/8 studs Comp Cam roller tip rockers and lifters MSD Distributor MSD 6AL electronic ign __________________ Project Name: LEMON DROP. Reconstruction started "December 2000". Projected completion date "Who knows" http://67-72chevytrucks.com/vboard/s...d.php?t=200082

05-01-2008, 08:41 AM	#2
El Jay Gone to greener pastures Join Date: May 2007 Location: Gateway to the Delta Posts: 7,354	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. __________________ '69 Chevy 1/2 T LWB Stepper: Daily Beater '72 GMC 3/4 T Fleet: Another Daily Beater '72 Plymouth Gran Coupe: ? "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 Last edited by El Jay; 05-01-2008 at 08:41 AM. Reason: spelling

05-01-2008, 09:37 AM	#3
Wreckless_71 Registered User Join Date: Apr 2007 Location: Kelso, WA Posts: 363	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... __________________ 1972 K10 4" lift, 35’s, 383 stroker, 700r4, current project. 1971 C10 3"/5" static drop, 355/350. "La Bamba.” The current daily driver.

05-01-2008, 12:58 PM	#4
HomerJ Registered User Join Date: Apr 2007 Location: Norman, OK Posts: 222	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. HomerJ __________________ 67 C-10 LWB "Cow-butt-spotted" (neighbor's term) - work in progress. 350/TH400/3.73 67 Chevelle SS Clone 454/TH400/3.73

05-01-2008, 06:55 PM	#5
jugernot Life, Be In It..... Join Date: Oct 2003 Location: Novato, California Posts: 1,498	Re: Is there a site that will help me determine the needed plug gap? thanks for the input. __________________ Project Name: LEMON DROP. Reconstruction started "December 2000". Projected completion date "Who knows" http://67-72chevytrucks.com/vboard/s...d.php?t=200082

05-01-2008, 08:28 PM	#6
powell72 Senior Member Join Date: Jan 2005 Location: Loveland Co. Posts: 3,098	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. __________________ Chris 74 Custom Deluxe SWB 350/350/3.73’s 99 2wd Silverado RCSB 5.3/4L60/3.90’s http://www.classictrucks.com/feature...short_bed.html

05-01-2008, 11:47 PM	#7
Blazer1970 Registered User Join Date: Dec 1999 Location: Old Mission, MI, USA Posts: 2,507	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. __________________ Tim

05-02-2008, 01:00 AM	#8
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	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.

05-02-2008, 02:10 AM	#9
hotrodhomi Registered User Join Date: Apr 2004 Location: Sacramento Posts: 3,737	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. __________________ '72 2wd blazer, bagged w/ watts link & EDC '72 C10 "Lowered Farm Truck" STOLEN 5-18-11 '66 impala ht

05-02-2008, 04:37 PM	#10
jugernot Life, Be In It..... Join Date: Oct 2003 Location: Novato, California Posts: 1,498	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. __________________ Project Name: LEMON DROP. Reconstruction started "December 2000". Projected completion date "Who knows" http://67-72chevytrucks.com/vboard/s...d.php?t=200082

05-02-2008, 04:43 PM	#11
71Farmtruck Junk Junkie Join Date: Oct 2007 Location: Humble, TX Posts: 123	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. __________________ Mike 71 Chevrolet C-10 Short Bed Stepside 81 GMC 1500 Sierra Classic Long Bed

05-02-2008, 05:56 PM	#12
Wreckless_71 Registered User Join Date: Apr 2007 Location: Kelso, WA Posts: 363	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... __________________ 1972 K10 4" lift, 35’s, 383 stroker, 700r4, current project. 1971 C10 3"/5" static drop, 355/350. "La Bamba.” The current daily driver.



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