thermactor plugs for e7 heads

[Tn-mustang]

Hi, I am putting a 1990 5.0 in my 66 mustang and will not be using the thermactor tube across the back of the heads. I have already taken it off and thown it away. Does anyone know what the size bolt/plug to put in them to close them off. I have tried a 5/8 steel bolt which was to big and 7/16 is to small. I have read 5/8, 14 mm etc. The local ford dealership says they have to order them and I don't want to have to wait on them for 3 weeks. My heads have all the holes ready to accept 7/16 bolts on the front so I am jsut looking for soemthing to close these off in the back. Thanks

 

[ninety15.0]

its a funky thread man...i think its like 12.5mm. get a thread guage and check it out...but i think its metric. Secondly, i know they sell the plugs directly b/c i have them in my heads too...but you can just break off the ceramic part of a spark plug and use that i believe. good luck man

 

[DavidNC]

I went to advance auto and picked up a couple grade 5 bolts off the shelf and placed washers underneath the bolt heads. Forgot the size, but it was standard.

 

[18mustangs]

You can get thermactor plugs at the Ford parts department for a cheap price, or from Summit or other performance outlets for about $3.00.
Tim

 

[legalize420]

You can get thermactor plugs at the Ford parts department for a cheap price, or from Summit or other performance outlets for about $3.00.
Tim

i got mine from summit for $3.

 

[gregpro50]

Go to your local engine builder/machine shop. They have piles of these things laying around. They usually just give them to me if I bring him a cup of coffee...

 

[Tn-mustang]

follow up

They are 5/8-11. I got a wire pipe cleaning brush and cleaned out all the old exhaust build up and a 5/8-11 bolt fits great. Thanks for the help