Trick Flow Cylinder Head Emission/Thermactor Plug 5.0L/5.8L

Trick Flow:
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  • Change Thread Hole Size
  • Zinc Plated Steel
  • 5/8"-11 Male Thread Pattern
  • Can Plug Air Passages

Trick Flow Emission and Thermactor Plug for Most Aftermarket 5.0L and 5.8L Cylinder Heads.

Most aftermarket cylinder heads are not side specific. These thermactor plugs are designed to plug into your heads, to change the thread size to allow you to use your factory accessory drive brackets. These plugs are also used to close off any air passages in your heads.

Made from steel and then zinc plated. Features a 5/8"-11 male thread pattern.

*Sold individually, use 2 per car.

California Residents: Proposition 65 Warning

Note: This item is not CARB (California Air Resource Board) exempt and is not legal for sale or use in the state of California.

Vehicle Fitment

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I have a regular coarse thread bolt 5/8"-11 Male Thread Pattern and it is too big. Do you make these any smaller?

Asked by: Smitty
Sorry this only comes in one size.
Answered by: rk cjpp
Date published: 2019-09-23

My 1966 289 engine uses 1/2" -20 thermactor plugs. The thermactor plugs on the web site are 5/8" not 1/2". Does anybody make a 1/2" plugs?

Asked by: JKD60
Maybe you could reduce it by using a helicoil.
Answered by: rk cjpp
Date published: 2019-06-26

Do these plugs fit 66 and later 289/302 heads with thermactor ports?

Asked by: Shinoda
This will fit heads that have the emission ports for the exhaust cross over tube.
Answered by: rk cjpp
Date published: 2017-09-28

Is it pack of two plugs or one?

Asked by: Rezor
They're sold individually.
Answered by: CJ Pony Parts
Date published: 2019-06-26
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