Pulled Smog - What to use to block holes in heads?

techlaf · Oct 17, 2010

'75 Stock 302 with carb. I'm taking the thermactor smog pump off and all its accoutrements (but I'm holding on to it just in case). I need to plug up the two holes in the heads where the smog equipment screwed in. It's about a 1.25" X 1" hole that's threaded at the bottom for a bolt. There is an open port inside the hole I'm guessing I need to block?

Can I just put a washer on the outside of the head and screw a bolt through the washer into the threads?

Anything else I should do when removing smog?

blubuckaroo · Oct 17, 2010

You have an early thermactor head. A heavy washer will work. I had a machine shop cut a steel slug with a step for the copper washer on some '77 heads. I can't remember if they had a 5/16" or a 3/8" bolt.

7elk · Oct 18, 2010

I recently did the same thing. Got freeze plugs from napa that I installed that did the trick. No real need to seal a washer with bolt.

blubuckaroo · Oct 18, 2010

7elk said:
I recently did the same thing. Got freeze plugs from napa that I installed that did the trick. No real need to seal a washer with bolt.

Will that hold up to exhaust heat?

66bronco74 · Oct 18, 2010

I did the freeze plug way - they held up fine. Tap them in snug - never popped out.

BFD305 · Oct 18, 2010

They sell Thermactor plugs. Should be able to get them at the parts store or off of ebay. They are cheap and look good when they are in. You just need to clean up the threads in the holes a bit and they well screw right in. You may want to thread a bolt in first just to be sure the threads are clean. Or just use a bolt.

The thread size in the head is 5/8-11.
The size of the thread in the Thermactor Plug (part # F4ZZ-6E086-A) is 5/16-18.
If you can't find the Thermactor Plugs, you can use a 5/8-11 x 3/4" long bolt from your local Hardware Store to plug the hole in the head.

Sturube · Oct 18, 2010

My old rig had a glob of what looked like brazing solder in the port on the original crossover pipe from when the PO disconnected the smog equipment. It wasn't pretty but it worked.

blubuckaroo · Oct 22, 2010

BFD305 said:
They sell Thermactor plugs. Should be able to get them at the parts store or off of ebay. They are cheap and look good when they are in. You just need to clean up the threads in the holes a bit and they well screw right in. You may want to thread a bolt in first just to be sure the threads are clean. Or just use a bolt.

The thread size in the head is 5/8-11.
The size of the thread in the Thermactor Plug (part # F4ZZ-6E086-A) is 5/16-18.
If you can't find the Thermactor Plugs, you can use a 5/8-11 x 3/4" long bolt from your local Hardware Store to plug the hole in the head.

You are talking about the later version Thermactor head. The ones in question have larger holes on the side of the head in addition to the ones on the ends.

Pulled Smog - What to use to block holes in heads?

techlaf

Sr. Member

blubuckaroo

Grease Monkey

7elk

Sr. Member

blubuckaroo

Grease Monkey

66bronco74

Jr. Member

BFD305

New Member

Sturube

Jr. Member

blubuckaroo

Grease Monkey

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