Spark Plug gap - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Rain City · 04-14-2009, 09:41 PM

I've looked this up on this forum and others but can't find a good answer.

My truck is a 81 c10, with a 350, aluminum heads, holley carb - what should I gap my plugs at? I bought new ones, and they're set at .03

BUT - Recently when I've been accelerating at highway speeds, it sort of "gurgles" on acceleration, popping almost.

The only thing I changed was plugs, any suggestions???

Rain City · 04-14-2009, 09:52 PM

Is this correct?? http://wiki.answers.com/Q/What_is_pl...evy_350_engine

.035 for points, and .045 with HEI distributor? How do I know which I have? Check out my engine...

**old Rusty C10** · 04-14-2009, 10:08 PM

if its a stock distributor it should be HEI most HEI have the coil in the top of the cap

Rain City · 04-14-2009, 10:14 PM

Quote:

Originally Posted by old Rusty C10

if its a stock distributor it should be HEI most HEI have the coil in the top of the cap

You're right, it is HEI Just looked, so go with .045?

dammitmitchell · 04-14-2009, 10:38 PM

.45 yeapppers dude..

dammitmitchell · 04-14-2009, 10:39 PM

p.s. where did you get those valve covers?
and the air filter dish?
that looks good man

gchemist · 04-14-2009, 10:51 PM

I run 0.045 on my ZZ4.
Specs: FR5LS Gap .035
Rapid Fire #5 Gap .045

Rain City · 04-15-2009, 10:54 AM

One of the spark plug 'ports' (dont know official name) is cracking spark plugs when I tighten it, anyone know anything about this?

Malo83 · 04-15-2009, 03:26 PM

I gap mine at .050 with a HyperTech Supercoil and it improved the idle and overall performance of the engine

enaberif · 04-15-2009, 07:59 PM

Quote:

Originally Posted by Rain City

One of the spark plug 'ports' (dont know official name) is cracking spark plugs when I tighten it, anyone know anything about this?

Sounds like your over tightening.

Hand tighten and then just snug them up.

They don't need to be that tight.

dammitmitchell · 04-15-2009, 09:16 PM

if you check your shop manual or the specific brand of plug's site they will have the torque specifications for each individual string of plugs..

81c10 · 02-01-2011, 11:38 PM

Wait. So if I have a coil on top of my distributor I def have HEI? I just ordered mad 8.5 wires NOT for HEI. Do I need to order HEI wires?
Posted via Mobile Device

Psycho71 · 02-02-2011, 12:26 AM

yes, coil on top is HEI. Will require plug wires for HEI, will have female boots on each end (90* at the dist terminals, and the specified straight or 90* at the plug). Standard points type plug wires will have male ends on the dist terminals.

gchemist · 02-02-2011, 02:24 AM

Oh, add a bigger air filter!! At mid to high RPMs you need more air!! Stock was 4" for gas engines. Your engine will run cooler too!

04-14-2009, 09:41 PM	#1
Rain City Registered User Join Date: Mar 2009 Location: Seattle, WA Posts: 32	Spark Plug gap I've looked this up on this forum and others but can't find a good answer. My truck is a 81 c10, with a 350, aluminum heads, holley carb - what should I gap my plugs at? I bought new ones, and they're set at .03 BUT - Recently when I've been accelerating at highway speeds, it sort of "gurgles" on acceleration, popping almost. The only thing I changed was plugs, any suggestions???

04-14-2009, 09:52 PM	#2
Rain City Registered User Join Date: Mar 2009 Location: Seattle, WA Posts: 32	Re: Spark Plug gap Is this correct?? http://wiki.answers.com/Q/What_is_pl...evy_350_engine .035 for points, and .045 with HEI distributor? How do I know which I have? Check out my engine...

04-14-2009, 10:08 PM	#3
old Rusty C10 Robert Olson Transport Join Date: Oct 2002 Location: recent transplant to NC USA Posts: 20,310	Re: Spark Plug gap if its a stock distributor it should be HEI most HEI have the coil in the top of the cap __________________ Bob 1951 International running on a squarebody chassis "If a man's worth is judged by the people he associates himself with, then i am the richest man in the world knowing some of the fine people of this board" http://67-72chevytrucks.com/vboard/a...t.php?f=25&a=9 (you can review the site rules here!) PM Me for your vehicle/parts hauling needs in the North East US or see my Facebook page Robert Olson Transport Live each day to the fullest.. you never know when fate is going to pull the rug out from under you... I hate cancer!!

04-14-2009, 10:39 PM	#6
dammitmitchell the pollock Join Date: May 2008 Location: abilene, texas Posts: 4,423	Re: Spark Plug gap p.s. where did you get those valve covers? and the air filter dish? that looks good man __________________ Jack of ALL trades, Master of none.. (but one... procrastination) Army vet 02-08 RIP El Jay! Miss you brother! http://67-72chevytrucks.com/vboard/s...d.php?t=343538 http://67-72chevytrucks.com/vboard/s...d.php?t=386042

04-14-2009, 10:51 PM	#7
gchemist BAD BOW-Silverado XST Join Date: May 2000 Location: Senior Member from Austin, TX Posts: 6,431	Re: Spark Plug gap I run 0.045 on my ZZ4. Specs: FR5LS Gap .035 Rapid Fire #5 Gap .045 __________________ Gerardo a.k.a. Mad Chemist Silverado XST videos

04-14-2009, 10:38 PM	#5
dammitmitchell the pollock Join Date: May 2008 Location: abilene, texas Posts: 4,423	Re: Spark Plug gap .45 yeapppers dude.. __________________ Jack of ALL trades, Master of none.. (but one... procrastination) Army vet 02-08 RIP El Jay! Miss you brother! http://67-72chevytrucks.com/vboard/s...d.php?t=343538 http://67-72chevytrucks.com/vboard/s...d.php?t=386042

04-15-2009, 10:54 AM	#8
Rain City Registered User Join Date: Mar 2009 Location: Seattle, WA Posts: 32	Re: Spark Plug gap One of the spark plug 'ports' (dont know official name) is cracking spark plugs when I tighten it, anyone know anything about this?

04-15-2009, 03:26 PM	#9
Malo83 Cruzzzn' Vet Join Date: Jan 2005 Location: Porterville,Ca. Posts: 1,918	Re: Spark Plug gap I gap mine at .050 with a HyperTech Supercoil and it improved the idle and overall performance of the engine

04-15-2009, 09:16 PM	#11
dammitmitchell the pollock Join Date: May 2008 Location: abilene, texas Posts: 4,423	Re: Spark Plug gap if you check your shop manual or the specific brand of plug's site they will have the torque specifications for each individual string of plugs.. __________________ Jack of ALL trades, Master of none.. (but one... procrastination) Army vet 02-08 RIP El Jay! Miss you brother! http://67-72chevytrucks.com/vboard/s...d.php?t=343538 http://67-72chevytrucks.com/vboard/s...d.php?t=386042

02-01-2011, 11:38 PM	#12
81c10 Registered User Join Date: Sep 2010 Location: Greensboro, NC. Posts: 42	Re: Spark Plug gap Wait. So if I have a coil on top of my distributor I def have HEI? I just ordered mad 8.5 wires NOT for HEI. Do I need to order HEI wires? Posted via Mobile Device

02-02-2011, 12:26 AM	#13
Psycho71 Registered User Join Date: Jan 2006 Location: Kaufman, Tx Posts: 827	Re: Spark Plug gap yes, coil on top is HEI. Will require plug wires for HEI, will have female boots on each end (90* at the dist terminals, and the specified straight or 90* at the plug). Standard points type plug wires will have male ends on the dist terminals. __________________ You only need two tools in life - WD-40 and Duct Tape. If it doesn't move and should, use the WD-40. If it shouldn't move and does, use the duct tape. If a hammer doesn't fix it, you have an electrical problem! Slot Cars, 1:24 Scale, 100MPH@100,000RPM, fastest things on wheels!

02-02-2011, 02:24 AM	#14
gchemist BAD BOW-Silverado XST Join Date: May 2000 Location: Senior Member from Austin, TX Posts: 6,431	Re: Spark Plug gap Oh, add a bigger air filter!! At mid to high RPMs you need more air!! Stock was 4" for gas engines. Your engine will run cooler too! __________________ Gerardo a.k.a. Mad Chemist Silverado XST videos Last edited by gchemist; 02-02-2011 at 02:25 AM.

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