Smog removed: how to cap manifolds?

[dec322]

1984 k10. The PO removed the cats.

I just finished my timing chain, water pump, oil pan gasket change and decided to pull the smog pump. Some of my vacuum lines are already plugged by PO. I am trying to figure out how to cap the pipe that comes off the top of the exhaust manifolds. I read an oil plug off of a dodge diesel but no specifics. See pic for reference.
Any insights?

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[1lejohn]

If it's regular pipe threads, use a pipe coupling and plug. Or you can remove the tubing from the manifolds and use pipe plugs on the holes in the manifolds.

 

[Edelbrock]

Ya, I would just go to Ace Hardware, Lowes, Home Depot etc and buy every cap that they have that has about the same diameter. Then go home and try one after another until you get a winner. Then just return the rest of the caps. Keep your receipt and its a quick and easy return. Another thing that works is to clamp a short rubber hose over that pipe and then stick a large bolt in the other end and hose clamp that in place. Its looks kinda ghetto, and doesn't seem like it would work - but it does work. That pipe doesn't actually get that hot, relatively speaking.

 

[dec322]

If it's regular pipe threads, use a pipe coupling and plug. Or you can remove the tubing from the manifolds and use pipe plugs on the holes in the manifolds.

I thought about removing the tubing but saw some pics of caps on these.

Ya, I would just go to Ace Hardware, Lowes, Home Depot etc and buy every cap that they have that has about the same diameter. Then go home and try one after another until you get a winner. Then just return the rest of the caps. Keep your receipt and its a quick and easy return. Another thing that works is to clamp a short rubber hose over that pipe and then stick a large bolt in the other end and hose clamp that in place. Its looks kinda ghetto, and doesn't seem like it would work - but it does work. That pipe doesn't actually get that hot, relatively speaking.

I have a ghetto fix with a plug in the hose but your ghetto fix would be less janky .
Ultimately, I want to do a ls swap. I use the truck to cruise so I’m not too worried about engine bay looks at the moment.

 

[edgephoto]

Get a 3/4" pipe cap or remove the tubes from the manifolds and order some brass 1/4" plugs to fill the holes.

 

[dec322]

I ended up picking up a couple of 1/2 pipe caps from Ace Hardware. I used a JB weld high temp paste in the threads to prevent gases something through (yep…it’s permanent). Pics of finished product and products used….for future search results

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[Edelbrock]

Looks good man. That should hold it.