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Spark Plug Gap... head or block?

  • Thread starter Thread starter nittanylion45
  • Start date Start date May 8, 2007
N

nittanylion45

New Member
Nov 22, 2006
13
0
0
May 8, 2007
#1
  • May 8, 2007
  • #1
Hi,

I have GT40P heads on a 71 302 block for my 65 conv.

Should I gap the plugs witht he head spec (2000 Exporer, 0.054") or standard 302 gap (.038")? I would think the head spec would be correct. But, I would like a confirmation.

Regards, Jim.
 

65fastbackresto

Active Member
Apr 13, 2007
1,229
7
39
AR
May 8, 2007
#2
  • May 8, 2007
  • #2
The head

Contains the combustion chamber, would be the head speck I assume....
 
8

86bluecobra

Advanced Member
Dec 20, 2004
4,265
12
69
B.C. Canada
May 8, 2007
#3
  • May 8, 2007
  • #3
Now from what I can determine and I maybe way off the efi stuff always has a larger gap then the carb guys. I'm not really sure why this is. I would start with a .044 gap and see what it is like. That being said the .038 I'm sure would work just fine.
 
B

BlackGMC

New Member
Feb 6, 2007
247
1
0
May 8, 2007
#4
  • May 8, 2007
  • #4
are you running a MSD box?
 
N

nittanylion45

New Member
Nov 22, 2006
13
0
0
May 8, 2007
#5
  • May 8, 2007
  • #5
Nope.

Just a pertronix coil and solid state ignition.
 

CraigMBA

New Member
Mar 24, 2007
783
1
0
Orange, CA
May 8, 2007
#6
  • May 8, 2007
  • #6
Do the smaller .038.

The heads don't require a certain gap, per say. The gap is determined by the ignition system.

Bigger ignition = more gap.
 
J

j69302

Active Member
Jan 31, 2006
325
1
29
May 8, 2007
#7
  • May 8, 2007
  • #7
heads are only concerned with spark plug reach. make sure you have the correct reach for your heads. reach is the threaded portion of the plug. too long and it could hit a piston or valve. too short and the plug wont be in the combustion chamber.

adjust the gap based on your ignition setup.
 
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