what plugs to run? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

dropped72shortbed · 04-10-2002, 11:48 PM

for my 350, it has HEI but the motor is old and needs rebuilding. it had some bosch plugs in it and they were at .028, the parts guy checked on a 75 350 to get HEI numbers and it said .060, he also said it recommended a colder plug than the one i had in it.

does it really matter the temp of the plug? if not then at least what gap should i shoot for? any idea?

71Blazer · 04-11-2002, 01:41 AM

Sorry no answer, just another question... with TPI/HEI what wires (and plugs) perform well without costing a fortune?

BobbyK · 04-11-2002, 02:09 AM

I have TPI + HEI but run the same plugs now that I did before I switched to TPI.I run any year chevy BIG BLOCK wire.I use a Delco R45TS plug gapped at .45.Works well for me.

A cold plug has a short insulator and dissapates heat better than a hot plug.A cold plug (depending on your driving habits)will quickly develope deposits of oil and carbon since it's not hot enough to burn them off.This may lead to plug fouling and possibly a misfire condition.

A hot plug extends farther into the combustion chamber.It runs hotter and for that reason it will have no deposits on it but due to the excessive heat the electrode will burn away quickly and possibly lead to pre-ignition.
The choice of plug depends on your driving .If the majority of your driving is in the city go with a hotter plug.If you drive the highway alot go with a colder plug.

All the info. I've provided came from the Chiltons manual.

------------------
"71"blazer,rust free(bought in Arizona),350SBC
(375HP),700R4,factory G.M. TPI.Living in Santa Barbara,California.Ongoing project.

O'l Buck · 04-11-2002, 02:44 AM

I'm using AC r45ts in my 350 with hei and carb. I think I gapped at .045

------------------
Ol' Buck: '72 Chevy 1/2T 4x4 shortbox stepside 350/350auto on '84
ralleys and 31/10.5s

Angel girl: 67 Cutlass convertible
330, 3spd stick

Greener: 90 GMC Jimmy
350/auto
Chad Stephens
Orleans,NE

no name yet: 72 442 under serious construction

**MJN** · 04-11-2002, 07:08 AM

Gap is supposed to be at .060" accorfing to factory manuals. I run AC R45TS and at .060 and it runs great. Also I have Accel 8mm wires.

**MJN** · 04-11-2002, 07:08 AM

Gap is supposed to be at .060" according to factory manuals. I run AC R45TS and at .060 and it runs great. Also I have Accel 8mm wires.

BubbaGreen · 04-11-2002, 07:19 AM

If you have an HEI dist...and the RAM-Horn
style exhaust manifolds, get plug wires for
a '75 Vette. They will fit great because
this is what was 'factory' for that model.

------------------
71 Chevy C-10 SWB Fleetside WAS:307w/3-on-the-tree NOW:350TBI/700R4/3.73
See it at www.prismnet.com/~grzanich

04-10-2002, 11:48 PM	#1
dropped72shortbed Registered User Join Date: Nov 2001 Posts: 303	what plugs to run? for my 350, it has HEI but the motor is old and needs rebuilding. it had some bosch plugs in it and they were at .028, the parts guy checked on a 75 350 to get HEI numbers and it said .060, he also said it recommended a colder plug than the one i had in it. does it really matter the temp of the plug? if not then at least what gap should i shoot for? any idea? __________________ Blake A. - Huntington Beach CA 72 c10 swb 5/5 drop, 350/350, partialy shaved, soon to be 5/7 on 20s.

04-11-2002, 01:41 AM	#2
71Blazer Goodbye Darlin' Join Date: Nov 2001 Location: Coupeville, WA USA Posts: 330	Sorry no answer, just another question... with TPI/HEI what wires (and plugs) perform well without costing a fortune? __________________ 1971 Blazer CST SOLD!

04-11-2002, 02:09 AM	#3
BobbyK Registered User Join Date: May 2000 Location: Petrolia,Ontario,Canada but working in Port Huron,Mi. Posts: 1,769	I have TPI + HEI but run the same plugs now that I did before I switched to TPI.I run any year chevy BIG BLOCK wire.I use a Delco R45TS plug gapped at .45.Works well for me. A cold plug has a short insulator and dissapates heat better than a hot plug.A cold plug (depending on your driving habits)will quickly develope deposits of oil and carbon since it's not hot enough to burn them off.This may lead to plug fouling and possibly a misfire condition. A hot plug extends farther into the combustion chamber.It runs hotter and for that reason it will have no deposits on it but due to the excessive heat the electrode will burn away quickly and possibly lead to pre-ignition. The choice of plug depends on your driving .If the majority of your driving is in the city go with a hotter plug.If you drive the highway alot go with a colder plug. All the info. I've provided came from the Chiltons manual. ------------------ "71"blazer,rust free(bought in Arizona),350SBC (375HP),700R4,factory G.M. TPI.Living in Santa Barbara,California.Ongoing project. __________________ 71 blazer,350SBC,approx.375HP,700R4,factory GM TPI.Dual electric fans,33x12.5x15 ATR on stock suspension. Petrolia,Ontario,Canada but working in Port Huron,MI. See ALL my Blazer pic's HERE

04-11-2002, 02:44 AM	#4
O'l Buck Recovering Truck Driver Join Date: Mar 2002 Location: Orleans, NE USA Posts: 1,883	I'm using AC r45ts in my 350 with hei and carb. I think I gapped at .045 ------------------ Ol' Buck: '72 Chevy 1/2T 4x4 shortbox stepside 350/350auto on '84 ralleys and 31/10.5s Angel girl: 67 Cutlass convertible 330, 3spd stick Greener: 90 GMC Jimmy 350/auto Chad Stephens Orleans,NE no name yet: 72 442 under serious construction __________________ 67 K-20 350, SM465, Eaton rear, 4.56 no spin option 00 Dodge 2500 4x4, 24V cummins, 5 speed Chad South Central Nebraska

04-11-2002, 07:08 AM	#5
MJN Registered User Join Date: Feb 2000 Location: Maquoketa, Ia/ Orr, Mn Posts: 2,966	Gap is supposed to be at .060" accorfing to factory manuals. I run AC R45TS and at .060 and it runs great. Also I have Accel 8mm wires. __________________ '51 South Bend Model "9A" '56 Chevy 3600 NAPCO '74 Chevy Cheyenne Super K20-restored on 37's '72 GMC Sierra Custom K2500- in progress '08 GMC Envoy Denali '12 GMC Sierra 2500HD Denali '17 GMC Yukon XL VCCA member #58596 http://www.nohrco.com

04-11-2002, 07:19 AM	#7
BubbaGreen Senior Member Join Date: Mar 2001 Location: Cedar Park, TX Posts: 686	If you have an HEI dist...and the RAM-Horn style exhaust manifolds, get plug wires for a '75 Vette. They will fit great because this is what was 'factory' for that model. ------------------ 71 Chevy C-10 SWB Fleetside WAS:307w/3-on-the-tree NOW:350TBI/700R4/3.73 See it at www.prismnet.com/~grzanich __________________ 71 Chevy C-10 SWB Fleetside RamJet-350/4L60e & Compushift/3.73Posi See it at www.prismnet.com/~grzanich



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