The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > 47 - Current classic GM Trucks > The 1967 - 1972 Chevrolet & GMC Pickups Message Board

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 09-27-2008, 06:04 PM   #1
Sport/Truck
Sierra Grande Club
 
Sport/Truck's Avatar
 
Join Date: Jan 2007
Location: New Mexico USA
Posts: 2,433
Plug requirements for 383 stroker/same as 350?

I'm wondering if a 383 uses the same spark plugs (heat range) as the 350.
I'm also using an HEI too. What gap should I use?
s/t
__________________
1971 GMC Sierra Grande, 1/2 ton short wide, original 4 bolt 010 020 block & heads. (matching #'s). 383 stroker, SMI q jet 750 cfm, Lunati Voodoo 60102 cam, Scorpion roller rockers, Spin Tech pro street mufflers with X pipe.
Sport/Truck is offline   Reply With Quote
Old 09-27-2008, 06:21 PM   #2
Arad68
Trucks N Tranzams
 
Arad68's Avatar
 
Join Date: Dec 2002
Location: North Las Vegas, Nevada
Posts: 816
Re: Plug requirements for 383 stroker/same as 350?

Spark plug requirements are based on numerous things, but the two most important are compression (compression will determine heat range) and reach. Here is a quick guide that I use and a website that is very useful.

http://www.sparkplugs.com/

Here are the recommendations from edelbrock. I believe the plug seats are flat, so you should use the washers (if they are tapered seats, you don't use the washer...)

Under 9.5 to 1 Compression

Champion ---------- RC12YC / 2071
NGK --------------- FR 4 / 5155 OR BCPR5ES / 6130
Autolite ------------ 3926
Motorcraft --------- AGSFP52
Accel Shorty ------- 0416S

Up to 10.5 to 1 Compression

Champion ----------- RC9YC / 2075
Autolite -------------- 3924
NGK ----------------- FR 5 / 7373 OR BCPR7ES / 3330
Accel Shorty -------- 0414S

11 to 1 Compression

Champion ------------ C63YC / 796
NGK ------------------ R5672A-8 / 7173

12 to 1 Compression

Champion ------------- C61YC / 785
NGK ------------------- R5672A-9 / 7405

"Reach" is where the electrode and grounding strap are placed in the combustion chamber. It is the length of the threaded end of the spark plug.
What kind of heads do you have?
__________________
Don

'68 Chevy LB 383 TH400/GV/373 posi
'56 Chevy 4WD SWB
'64 Chevy short stepside
'79 Trans Am 455/TH2004R/12blt/4whldisc
95 Kia (Wifes car)
2002 S-10 extended cab pickup
"God punishes small sins immediately"
Arad68 is offline   Reply With Quote
Old 09-27-2008, 06:39 PM   #3
Sport/Truck
Sierra Grande Club
 
Sport/Truck's Avatar
 
Join Date: Jan 2007
Location: New Mexico USA
Posts: 2,433
Re: Plug requirements for 383 stroker/same as 350?

Thanks for the info.
I have NGK 7052 / YR5 v-power. I'm not sure where they fit in your compression chart....I'm at about 10:1 compression.
s/t
__________________
1971 GMC Sierra Grande, 1/2 ton short wide, original 4 bolt 010 020 block & heads. (matching #'s). 383 stroker, SMI q jet 750 cfm, Lunati Voodoo 60102 cam, Scorpion roller rockers, Spin Tech pro street mufflers with X pipe.

Last edited by Sport/Truck; 09-27-2008 at 06:40 PM.
Sport/Truck is offline   Reply With Quote
Old 09-27-2008, 06:50 PM   #4
Arad68
Trucks N Tranzams
 
Arad68's Avatar
 
Join Date: Dec 2002
Location: North Las Vegas, Nevada
Posts: 816
Re: Plug requirements for 383 stroker/same as 350?

Go to www.sparkplugs.com. At the bottom of the page is a link called sparkplug 411. Go to the bottom of this page and you will find a numbering system for NGK
__________________
Don

'68 Chevy LB 383 TH400/GV/373 posi
'56 Chevy 4WD SWB
'64 Chevy short stepside
'79 Trans Am 455/TH2004R/12blt/4whldisc
95 Kia (Wifes car)
2002 S-10 extended cab pickup
"God punishes small sins immediately"
Arad68 is offline   Reply With Quote
Old 09-27-2008, 11:40 PM   #5
Sport/Truck
Sierra Grande Club
 
Sport/Truck's Avatar
 
Join Date: Jan 2007
Location: New Mexico USA
Posts: 2,433
Re: Plug requirements for 383 stroker/same as 350?

OK, thanks, looks like I'm right in the ball park with the heat range.
What gap should I set these at since I'm using HEI? They come factory set at .039.
s/t
__________________
1971 GMC Sierra Grande, 1/2 ton short wide, original 4 bolt 010 020 block & heads. (matching #'s). 383 stroker, SMI q jet 750 cfm, Lunati Voodoo 60102 cam, Scorpion roller rockers, Spin Tech pro street mufflers with X pipe.

Last edited by Sport/Truck; 09-27-2008 at 11:42 PM.
Sport/Truck is offline   Reply With Quote
Old 09-28-2008, 12:54 AM   #6
Arad68
Trucks N Tranzams
 
Arad68's Avatar
 
Join Date: Dec 2002
Location: North Las Vegas, Nevada
Posts: 816
Re: Plug requirements for 383 stroker/same as 350?

.039 is good. Larger gap tends to dissipate
or diminish the spark. No more than .045
__________________
Don

'68 Chevy LB 383 TH400/GV/373 posi
'56 Chevy 4WD SWB
'64 Chevy short stepside
'79 Trans Am 455/TH2004R/12blt/4whldisc
95 Kia (Wifes car)
2002 S-10 extended cab pickup
"God punishes small sins immediately"

Last edited by Arad68; 09-28-2008 at 12:55 AM.
Arad68 is offline   Reply With Quote
Old 09-28-2008, 10:28 AM   #7
Sport/Truck
Sierra Grande Club
 
Sport/Truck's Avatar
 
Join Date: Jan 2007
Location: New Mexico USA
Posts: 2,433
Re: Plug requirements for 383 stroker/same as 350?

Thanks Don....I'll get these put in today!
s/t
__________________
1971 GMC Sierra Grande, 1/2 ton short wide, original 4 bolt 010 020 block & heads. (matching #'s). 383 stroker, SMI q jet 750 cfm, Lunati Voodoo 60102 cam, Scorpion roller rockers, Spin Tech pro street mufflers with X pipe.
Sport/Truck is offline   Reply With Quote
Old 09-28-2008, 10:28 AM   #8
Sport/Truck
Sierra Grande Club
 
Sport/Truck's Avatar
 
Join Date: Jan 2007
Location: New Mexico USA
Posts: 2,433
Re: Plug requirements for 383 stroker/same as 350?

Thanks Don....I'll get these put in today!
s/t
__________________
1971 GMC Sierra Grande, 1/2 ton short wide, original 4 bolt 010 020 block & heads. (matching #'s). 383 stroker, SMI q jet 750 cfm, Lunati Voodoo 60102 cam, Scorpion roller rockers, Spin Tech pro street mufflers with X pipe.
Sport/Truck is offline   Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 06:43 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright 1997-2022 67-72chevytrucks.com