Re: Emission plugs

[John Hofstetter <hofs@domain.elided>]

>When the air injection manifolds and connecting pipes rust away, many folks
>simply remove the mess and plug the threaded holes in the head with the
>special IH plugs.  On my 392, I punched out the hollow tubes so they are no
>longer blocking part of the exhaust stream.  I'll fit common 1/2-20 x 1/2"
>set screws to plug the remaining threaded holes when I put the heads back
>together.
>
>Regards,
>
>John L.

What I can't seem to remember is: If you leave the tubes, can you plug 
them with a threaded device? If you remove the tubes, does it now take a 
different size plug. Seems to me as if the brass plugs I used were 1/8th 
pipe plugs, not near the 1/2 inch you mention. Gotta remember it's been 
20 years since I took that air injection system off. I guess I could go 
look at my Scout, but it's easier to ask you.
John H.