Spark Plugs after Hei Conversion ???? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Bill72BB · 11-25-2002, 11:57 AM

BB got a HEI over the weekend and as long as I was going to pull the plugs to gap them at .44 , I was wondering if I should be running a different plug say for a 77-84 BB with Hei ???
I'm running AC44t right now.

Thanks

JimKshortstep4x4 · 11-25-2002, 12:17 PM

We run AC R45TSX in our engines with HEI. Most of our driving is short trips, so we run a little hotter plug and a gap of .050. With the "X" designation, it is easier to set a wider gap.

Jim

Ackattack · 11-25-2002, 12:30 PM

I wouldn't really worry about changing it.

Gene · 11-25-2002, 06:20 PM

I agree with ackattack, I changed mine over to HEI and left the gaps the same and kept the same plugs. Worked out fine.

OLDCHEV4X4 · 11-25-2002, 08:53 PM

I used the same plugs and opened the gap to .045

wbmorris87 · 11-25-2002, 09:39 PM

Use the plug for the year of the motor, but open up the gap. Chevy says HEI = .045 to .060. I use .060 to get the hottest spark for the bang,(uses all available electricity to jump the gap.)

Longhorn Man · 11-26-2002, 12:43 AM

Quote:

Originally posted by wbmorris87
Use the plug for the year of the motor, but open up the gap. Chevy says HEI = .045 to .060. I use .060 to get the hottest spark for the bang,(uses all available electricity to jump the gap.)

Only problem with that, is you'll end up burning up coils and wires and all that Jazz.
When The general went to HEI, they started with a rather large .060 plug gap, and they realized the coils were burning out, and caps were melting...ect. Turns out, the added resistance was creating way too much heat.
If you were to look, you'll see that the year after HEI was introduced, the gap went down to .055 or so, and later down again and has stayed on .045 for many years now.

69sixpackbee · 11-26-2002, 12:45 AM

Bill,
I run my R45TS plugs @ .045" gap. No more needed. BTW, which wires did you end up getting?

cableguy0 · 11-26-2002, 01:09 AM

with a stock hei unit i would get a plug with a .045 gap. as longhorn said anymore will burn out a stock coil and module and basically cause meltdown of your dizzy. now if u are running an aftermarket hei suck as an msd or proform with a 50,000 volt coil it really wont hurt it to run a .055 or so it'll actually help ur gas mileage and give u a little more power. for those of u guys who are only running a .035 gap with the hei open those plugs up.u will notice a difference in gas mileage and possibly a little more power

Bill72BB · 11-26-2002, 01:09 AM

Thanks ; for all the info everyone , I went and got AC R45TS and gapped them at .44 .

Bud : I got the BB wire'e for a HEI 77-82 fit great .so far so good with the HEi .

Had 22% at 2000 rpm with the old Dist. the HEI has 21 % at 2000.

kombreeze · 07-11-2006, 11:17 AM

Each engine may vary. You may have to play with a set of different plugs each time...Either way run a couple of recommended suggestions and inspect the plugs....don't want to underestimate the damage that can be done for using the wrong plug combination.

glock35ipsc · 07-11-2006, 11:23 AM

This post is almost 4 years old.......... I betcha he has figgered it out by now

BTW,

to the boards!

11-25-2002, 11:57 AM	#1
Bill72BB Thats the Hillbilly way Join Date: Jul 2001 Location: Torrance,Ca Posts: 5,980	Spark Plugs after Hei Conversion ???? BB got a HEI over the weekend and as long as I was going to pull the plugs to gap them at .44 , I was wondering if I should be running a different plug say for a 77-84 BB with Hei ??? I'm running AC44t right now. Thanks __________________ BILL Torrance Calif 90504 Member DUF Club Member Old Farts Club 72 3/4ton Custom Camper BB402/400 trans Dynomax Cerama-coat headers , Hei distributor ,Edelbrock 1411 air,ps,pb,leafsprings ,98 chevy 60/40 seat,S10 shoulder belts tilt,3.54 Dana 60 rear. 16" Eagle wheels with LT265/75 16 tires,Gaylord Lid,H4 headlights with 100W relay conversion. " If I knew I was going to live this long I would have taken better care of myself " Marriage changes passion...suddenly you're in bed with a relative. A GUY'S PRAYER.... Lord, I pray for a nympho with huge boobs who owns a liquor store and likes to fish and hunt and has a Harley .Amen ,

11-25-2002, 12:30 PM	#3
Ackattack Senior Member Join Date: Aug 2002 Location: Valley Center KS Posts: 3,525	I wouldn't really worry about changing it. __________________ Project Bruiser: 68 Pro-Touring C-10 5.3L / 4L60E Project Ironhide: 97 GMC Crew Cab 4x4 Cummins SOLD: '69 GMC 1/2T SWB TBI'd: Project No Buck Assembly Manual Index Sign up Thread!!! Factory Service Manual Index

11-25-2002, 06:20 PM	#4
Gene Registered User Join Date: Aug 2002 Location: Muskogee, Oklahoma Posts: 2,914	I agree with ackattack, I changed mine over to HEI and left the gaps the same and kept the same plugs. Worked out fine. __________________ 1971 SWB 4X4 Build BOARD MEMBER #5448 BOOMER SOONER!!!!

11-25-2002, 08:53 PM	#5
OLDCHEV4X4 Registered User Join Date: Apr 2000 Location: Chester County PA, USA Posts: 1,228	I used the same plugs and opened the gap to .045 __________________ 72 k/10 short wideside 72 k/5 Blazer 72 K/5 Blazer - obstacle course racer 72 custom/10 8' bed 70 K/5 Blazer 67 C-30 GMC Flat bed 86 GMC K2500 Plow Truck 85 GMC K3500 84 M1008 85 M1008 77 G30 Motor Home 72 Sears 12hp Tractor Glenmoore, Pennsylvania

11-26-2002, 01:09 AM	#9
cableguy0 Senior Member Join Date: Apr 2000 Location: Delta,Pa Posts: 14,950	with a stock hei unit i would get a plug with a .045 gap. as longhorn said anymore will burn out a stock coil and module and basically cause meltdown of your dizzy. now if u are running an aftermarket hei suck as an msd or proform with a 50,000 volt coil it really wont hurt it to run a .055 or so it'll actually help ur gas mileage and give u a little more power. for those of u guys who are only running a .035 gap with the hei open those plugs up.u will notice a difference in gas mileage and possibly a little more power __________________ Owner of North Point Car Care in Dundalk Md. We specialize in custom exhaust on both modern and classic vehicles. We are a full service auto shop from classics to modern vehicles. Feel free to contact me with questions. I will give a 10% discount to any board member.

11-25-2002, 12:17 PM	#2
JimKshortstep4x4 Senior Member Join Date: Jul 2001 Location: Muskegon,MI,USA Posts: 6,026	We run AC R45TSX in our engines with HEI. Most of our driving is short trips, so we run a little hotter plug and a gap of .050. With the "X" designation, it is easier to set a wider gap. Jim

11-25-2002, 09:39 PM	#6
wbmorris87 Registered User Join Date: Apr 2001 Location: Fallon, NV Posts: 24	Use the plug for the year of the motor, but open up the gap. Chevy says HEI = .045 to .060. I use .060 to get the hottest spark for the bang,(uses all available electricity to jump the gap.)

11-26-2002, 12:45 AM	#8
69sixpackbee Registered User Join Date: Jan 2001 Location: Sabinal, Texas Posts: 1,706	Bill, I run my R45TS plugs @ .045" gap. No more needed. BTW, which wires did you end up getting?

07-11-2006, 11:17 AM	#11
kombreeze Registered User Join Date: Jul 2006 Location: Fresno, Ca Posts: 154	Re: Spark Plugs after Hei Conversion ???? Each engine may vary. You may have to play with a set of different plugs each time...Either way run a couple of recommended suggestions and inspect the plugs....don't want to underestimate the damage that can be done for using the wrong plug combination.

07-11-2006, 11:23 AM	#12
glock35ipsc Next project: 1970 K10 Join Date: Feb 2004 Location: Fort Collins, Colo 80524 Posts: 6,685	Re: Spark Plugs after Hei Conversion ???? This post is almost 4 years old.......... I betcha he has figgered it out by now BTW, to the boards! __________________ *Bob* 1970 Chevy K10 LWB "Goldie" 350/TH350 *next project!!* 1981 Chevy C10 LWB 355/TH350 - My son's truck LS SWAP FORUM! Tons of LS swap info here! PLEASE CLICK HERE TO SUPPORT THE GREATEST BOARD ON THE NET! CLICK HERE FOR THE FAQ INDEX by KRUE

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