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Thermactor Insert Kit, Smog Hole Plug, Threaded Head Insert, Accessory Bushing/Insert, SB Ford, F4ZZ-6E086-A

  • Thermactor Kit
  • Includes: Thermactor Inserts, 5/8"-11 Tap and Installation Tool
  • Thermactor Inserts & Install Tool
Thermactor Kit
Calculated at checkout

Product Description

Small Block Ford Smog Inserts

Thermactor Insert Kit, Includes: 1 Tap, 4 Thermactor Inserts and 1 Installation Tool

Thermactor Inserts Replace Ford # F4ZZ-6E086-A

This kit require custom machine work, please allow 7-10 days before shipment.


We put this kit together so virtually anyone can install new thermactor inserts in new or used heads. We checked the forums and various sites and noted many of them were selling thermactor inserts but no one offered a kit with everything needed to cover all possible conditions one might run up against when needing to install thermactor insert(s) quickly.

This basic kit includes: 4 Thermactor Inserts, 1 Bottoming Tap and 1 Installation Driver.

We noticed some folks had trouble installing them using the screw slot on the insert and others couldn't get them installed all the way because there was too much carbon build up in the threads.

Sometimes new heads come with the insert installed on the wrong side of one head and they need to install an insert in the other side so they can mount required accessories.

With the basic kit, you'll get a new 5/8"-11 NC bottoming tap, 4 thermactor plugs and the installation tool which is made up using a fully threaded Grade 5 Bolt and a long 5/8" drive nut which is stepped down on one end. The stepped down end butts up to the thermactor insert just right and allows the insert to be driven below the heads surface if needed to become tight. The tool is easy to remove from the insert after installation. Just hold the bolt head and loosen the drive nut. Simple yet effective.

If the the thermactor threads in the cylinder head have carbon build-up, use the 5/8"-11 tap to clean up the threads. (Be sure to use a little oil on the tap, do not use dry)


      The Basic Kit includes:

  • 4- Thermactor Plugs, made in the USA
  • 1-5/8"-11 NC Bottoming Tap
  • One Installation Tool (as shown in the pictures)


Customers interested in ordering the kit with just two thermactor inserts can do so and those who want more than 4 inserts can add 4 or 8 more inserts. Just select the appropriate option towards the top of the page. ONLY CHECK ONE OPTION FROM THE CHECK LIST BEFORE ADDING TO THE CART.

Note: We never thought we would have to say this but... if the heads you're working on are not drilled for use with a thermactor, then you won't need thermactor plugs or this kit! Heads which are drilled for thermactor use have large 5/8"-11 NC threads for the thermactor plug to screw into to. If your SBF heads have 7/16-18 NC threads, don't order thermactor inserts or install tools! Enough said.