Smog ports 360

[MOBodyman]

Putting in an 80's 360 and using '68 318 exhaust manifolds. How do you plug the little holes below the exhaust ports? Are all of them open? It appears the middle 2 are open on my motor but the outer 2 don't go too deep.
TIA,
Dallas

 

[C130 Chief]

A 1/4-20 tap and 8 setscrews work well.

 

[HemiEd]

A 1/4-20 tap and 8 setscrews work well.

I just did this on Saturday. Most of mine were carboned up, and closed off. Ran a drill bit in to clean them out, then did the set screw thing.

 

[MOBodyman]

Thanks for the info.
Dallas

 

[70DartMike]

I used a tap, and used flat headed allen key screws, and grinded the heads flat.