Bizarre 302 spark plug problems

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chuck1022

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• Apr 25, 2017

• #1

Went to parts store and bought new spark plugs. Got home and couldn't install them. The new plugs dont have enough thread to reach into my heads. The plugs i pulled out were champion 7981. They have a thread reach .9 inches. The oem plugs have a reach of .45 or something. I swapped them out to the 7981 plug and these are used for 4cyl fords...not 302. Anyone seen this before

 

Timmy390

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• Apr 25, 2017

• #2

What heads are you running? For example, plugs that fit E7 heads will not fit GT40P heads. The 40P's need a longer threaded section

Tim

 

blubuckaroo

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• Apr 25, 2017

• #3

What is the year model and history on the motor?

 

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chuck1022

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• Apr 25, 2017

• #4

blubuckaroo said:

What is the year model and history on the motor?

Click to expand...

1977 . Wss told the motor was "rebuilt". I will try and upload a picture of where the spark plug goes. Any specfic areas that i could take a picture of to help figure out wtf is going on

 

blubuckaroo

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• Apr 25, 2017

• #5

The thread size and tapered seat are correct for that motor, but the reach is way long.
I wonder if someone has bored out part of the threads in the head, or installed some sort of sleeve?

 

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chuck1022

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• Apr 25, 2017

• #6

Swapping plugs, will send picture

 

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chuck1022

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• #7

Timmy390 said:

What heads are you running? For example, plugs that fit E7 heads will not fit GT40P heads. The 40P's need a longer threaded section

Tim

Click to expand...

where do i tell which heads they are.

 

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chuck1022

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• Apr 25, 2017

• #8

Do these pictures help at all

 

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Timmy390

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• Apr 25, 2017

• #9

chuck1022 said:

where do i tell which heads they are.

Click to expand...

Should be some numbers under the valve cover on the heads.

Tim

 

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chuck1022

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• Apr 25, 2017

• #10

runs great, no problems there. 14-15 mpg, starts at a tap of the key.... i have driven the truck more in the last 2 months then the last 2 owners in 25-30 years...just sat in their garage holding down the concrete..........any help would be great

 

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chuck1022

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• Apr 25, 2017

• #11

Timmy390 said:

Should be some numbers under the valve cover on the heads.

Tim

Click to expand...

haha...damnit!!!!! never easy.

 

73azbronco

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• Apr 25, 2017

• #12

Put back whats in there. Don't mess with success. Not sure but that 7981 part number comes up as an Explorer motor, P head maybe?

 

Timmy390

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• Apr 25, 2017

• #13

That big "S" cast in the corner of the head points to E6SE heads

R = E5AE
S = E6SE
T = E7TE

Think they came out in 1986?? One you only on the Stang but stayed longer in the Vic's T-birds etc. Replaced with the E7 heads which were still around in 1996 on 351W's

Tim

 

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chuck1022

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• Apr 25, 2017

• #14

Timmy390 said:

That big "S" cast in the corner of the head points to E6SE heads

R = E5AE
S = E6SE
T = E7TE

Think they came out in 1986?? One you only on the Stang but stayed longer in the Vic's T-birds etc. Replaced with the E7 heads which were still around in 1996 on 351W's

Tim

Click to expand...

BINGO Tim. I checked the plugs for a 1986 mustang and they are the 7981!!!!!! not sure what that all means other than I am gonna put the plugs back in and keep driving it

 

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chuck1022

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• Apr 25, 2017

• #15

quick google search of e6 heads showed less than favorable opinions of this head. THat being said it works fine on my truck and I am not going to upset the universe by swapping them out of a perfectly good running motor. In the future, what are the heads I should be looking for when I rebuild this motor? my truck is a stocker, so i do not need big horsepower or rockcrawling stuff.

 

Timmy390

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• Apr 25, 2017

• #16

E7's are an upgrade. GT40 is even better and GT40P is even a touch better than the 40 non P. Then you get in to aluminium

P heads have unique spark plug angles so standard headers and exhaust manifolds do not fit. Some will fit with modifications. I'm running P heads and run Bronco Hut shorty headers. Fit great with no modification needed.

Tim

 

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chuck1022

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• Apr 25, 2017

• #17

Timmy390 said:

E7's are an upgrade. GT40 is even better and GT40P is even a touch better than the 40 non P. Then you get in to aluminium

P heads have unique spark plug angles so standard headers and exhaust manifolds do not fit. Some will fit with modifications. I'm running P heads and run Bronco Hut shorty headers. Fit great with no modification needed.

Tim

Click to expand...

I wanna keep stock exhaust manifolds, so i will look for e7 or gt40 non p.. rhanks