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Discussion Starter #1
I have a couple of check valves of some sort from the smog/air pump we took off during my holley sniper installation, picture is here:

(desc: It's a tube that bolts into the front of the head and connects to a hose)

I'd like to remove those and seal up the heads as we believe this is causing the car to run poorly under hard acceleration - can someone point me to the correct part to do this, I'm not having success searching them up myself, closest I've found are something like this:


But those don't seem to fit the space in the cylinder head, by that I mean this spot here:


Any help would be appreciated, I've seen a lot of potential solutions but I'm not sure what the right call is to plug this up and (perhaps) fix some of the stumbling I've had.
 

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I've never seen that check valve thing in your 1st photo. What year is the engine?
The plugs in your link are for plugging the holes in the exhaust ports where the air injection manifolds attach. Here is a photo of a 1968 289/302 smog system. The air injection manifolds are at the bottom.
 

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Discussion Starter #3
It's the original 67 289 - I've done a bit more research and it looks like I need "Thermactor" plugs - but these are threaded and go into the front of the head, I'm curious now if thats it or do I need to plug the larger holes too ... very odd stuff.
 

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I've never seen that check valve thing in your 1st photo. What year is the engine?
The plugs in your link are for plugging the holes in the exhaust ports where the air injection manifolds attach. Here is a photo of a 1968 289/302 smog system. The air injection manifolds are at the bottom.
It’s a first gen system. I was just looking at mine today wondering if I should remove it.

For the OP you’ll need to remove all the plumbing and plug the vacuum port that links to the anti backfire valve. The thermactor delete is pretty common. You should be able to plug them with standard plugs. Those can still fetch some dough if someone is doing a concours restoration of a 67 California market car.
 

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If you need to plug the holes in the ends of the heads, use these, but on a used head the threaded holes in the heads must be clean or the plugs won't go in completely.
 
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