blocking off exhaust holes on rear of 5.0 heads?

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MustangBill87

New Member

Jul 14, 2009

39

0

0

Sep 29, 2009

#1

• Sep 29, 2009

• #1

Whats up? I have an 87 GT that I am converting to a carb set-up for track use of course. My question is this, what are the holes on the rear of each cylinder head for and is it ok to plug them or should the be recirculated to the exhaust. Thanks for your help!!!

 

1991notchbackLX

Active Member

Dec 25, 2007

1,483

47

48

New York

Sep 29, 2009

#2

• Sep 29, 2009

• #2

Pull your smog equipment and block them off if that's your intention. I've heard of everything ranging from just buying some bolts from a hardware store to using two old spark plugs with the ceramic broken off to plug them up.

 

cenok is family

15 Year Member

Jun 25, 2003

1,409

69

79

Norman, Ok

Sep 29, 2009

#3

• Sep 29, 2009

• #3

they are for the smog pump. get a couple metal pipe plugs or bolts to plug them. make sure they seal off all the way

 

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MustangBill87

New Member

Jul 14, 2009

39

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0

Sep 29, 2009

#4

• Sep 29, 2009

• #4

Thanks for your help, did not want to hurt the stang so I figured I would ask the seasoned veteran's.

 

Chrome_Rust

Member

Dec 5, 2008

530

1

17

Findlay, Ohio

Sep 29, 2009

#5

• Sep 29, 2009

• #5

I have a set of E7's that I am porting, I welded up the port in the exhaust and i welded up the holes in the back of the heads. Guess you could use a pipe plug...

 

liljoe07

5 Year Member

Feb 18, 2009

1,622

363

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Cartersville,Ga

Sep 29, 2009

#6

• Sep 29, 2009

• #6

5/8-11 thread set screw or bolt is what you need.

 

N

-Nick-

New Member

Aug 6, 2009

25

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0

Sep 30, 2009

#7

• Sep 30, 2009

• #7

make sure you are running a open breather on the valve covers then...

 

cenok is family

15 Year Member

Jun 25, 2003

1,409

69

79

Norman, Ok

Sep 30, 2009

#8

• Sep 30, 2009

• #8

-Nick- said:

make sure you are running a open breather on the valve covers then...

Click to expand...

he's not talking about the PCV system. plugging the holes for the smog pump has nothing to do with crankcase ventilation.

 

2000xp8

SN Certified Technician

Aug 8, 2003

8,037

1,625

194

NJ

Sep 30, 2009

#9

• Sep 30, 2009

• #9

Ford sells the proper plugs to put in the holes, they are only a couple of bucks and are physically available at the ford dealer.
Unfortunately i forgot what i asked for when i got them.

 

1991notchbackLX

Active Member

Dec 25, 2007

1,483

47

48

New York

Sep 30, 2009

#10

• Sep 30, 2009

• #10

2000xp8 said:

Ford sells the proper plugs to put in the holes, they are only a couple of bucks and are physically available at the ford dealer.
Unfortunately i forgot what i asked for when i got them.

Click to expand...

thermactor plugs?

 

liljoe07

5 Year Member

Feb 18, 2009

1,622

363

124

Cartersville,Ga

Sep 30, 2009

#11

• Sep 30, 2009

• #11

1991notchbackLX said:

thermactor plugs?

Click to expand...

Yup

 

J

Joey7508

Member

Oct 23, 2005

198

0

17

Kerrville TX

Oct 2, 2009

#12

• Oct 2, 2009

• #12

napa in my town sells thermactor plugs or did. You can order them thrugh cjpony but they are 12$ a piece

 

B

black'vert

New Member

Apr 20, 2004

34

1

0

Oct 2, 2009

#13

• Oct 2, 2009

• #13

just take off the smog crossover tube, chop the ends off and install them on the opposite heads .....effectively flipping them around so the holes are blocked by the backside of the flange.

 

Reactions: tsiemens

H

hubstang

Member

Aug 29, 2010

4

4

14

Dec 10, 2019

#14

• Dec 10, 2019

• #14

I found these block off plates that bolt on from LMR.

SVE Smog Port Block Off Plate Kit 5.0/5.8 - LMR.com

Block off the smog ports on your Mustang 5.0 or 5.8 not originally equipped with smog equipment using this SVE smog port block off kit!

lmr.com

 

Reactions: Gs1987GT and General karthief

E

Exrace89GT

Member

Mar 29, 2019

90

16

18

Lompoc, CA

Dec 10, 2019

#15

• Dec 10, 2019

• #15

Make sure you run a tap in to clean the carbon out of the threads.

 

Reactions: General karthief

Mustang5L5

That is…until I whipped out my Bissell

Mod Dude

Feb 18, 2001

43,265

17,952

224

Massachusetts

Dec 13, 2019

#16

• Dec 13, 2019

• #16

Those things were totally clogged up on my e7s. Definitely chase the threads with a 5/8-11 thread cleaner before attempting to screw anything in,m

 

Reactions: General karthief

tsiemens

my welding skills arent really skills

Jul 14, 2018

136

26

38

ontario

Dec 15, 2019

#17

• Dec 15, 2019

• #17

I bought the plugs not knowing how bad the carbon build up would be so I ended up reversing the plates as another guy here mentioned

 

mattys91gt

Active Member

Feb 3, 2022

391

26

38

Plymouth Massachusetts

Jun 29, 2022

#18

• Jun 29, 2022

• #18

tsiemens said:

I bought the plugs not knowing how bad the carbon build up would be so I ended up reversing the plates as another guy here mentioned

Click to expand...

did this work for u I'm still getting a leak

 

C

Chuckster101

Member

Oct 3, 2024

32

5

18

St. Aug. Fl. 32084

Oct 18, 2024

#19

• Oct 18, 2024

• #19

hubstang said:

I found these block off plates that bolt on from LMR.

SVE Smog Port Block Off Plate Kit 5.0/5.8 - LMR.com

Block off the smog ports on your Mustang 5.0 or 5.8 not originally equipped with smog equipment using this SVE smog port block off kit!

lmr.com

Click to expand...

45.00 bucks ! No thanks !

 

C

Chuckster101

Member

Oct 3, 2024

32

5

18

St. Aug. Fl. 32084

Oct 18, 2024

#20

• Oct 18, 2024

• #20

45.00 bucks ,no way in ….