9165pt0

trying to fix any leaks in my car. im running gt40 iron heads. and no thermactor air hoses hooked up. just wondering what size the holes are? and how many are there, because heads are in car so i cant see the holes, but on the passenger side head i can feel 3 holes.

does any1 have a pic, or know if all 3 should be plugged?

87 T TOP GT302

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Fittings & Hoses > Trick Flow® Small Block Ford Thermactor Plugs
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Trick Flow® Small Block Ford Thermactor Plugs
Plug fittings for your heads.
Trick Flow® small block Ford thermactor plugs are designed to plug into your heads to change the thread size. These plugs are also used to close off any air passages in your heads.


The other 2 holes are bolt holes for the tube that runs across the back of the heads.

AdderMk2

You only need to plug the big holes. There is one in each head. They are 5/8-11 ... You can buy bolts at a hardware store. Try to get them 1" long, and use a washer.

Tony71502

Were those heads used before? I'm guessing yes. Those bolts or plugs, whichever route you go, will be a real pain in the *** to get in if those threads in the heads are caked up with carbon.

Project 5.GO!

My GT40 heads didn't even have the holes, so I left the tube out.

AdderMk2

They were either already plugged, or explorer heads.

Project 5.GO!

I don't remember them being plugged, unless they were welded shut, and perfectly matched to the surrounding metal.

According to the bars, the GT stamp, and the ease with which my spark plugs clear my headers, they aren't P heads.

Project 5.GO!

My bad, now that I look at the photos, the ports are there, but they seem bigger than the ones on the stock heads, and they were plugged.

9165pt0

picked up 2 5/8 11 bolts. and they were too big. so i went back and grabbed 1/2 11 bolts. too big. not sure whats going on here. maybe i dont have the thermactor holes back there. ill have to find a pic of the holes with the heads off, so i can see whats different with these heads. thanks guys.

AdderMk2

Post pictures. Your thermactor holes might not actually be there, or they already have the reducing inserts in them (which step down to 7/16-14)