The quick fix for the A.I.R. system plumbing is to run a 1/4" NPT tap into the hole a few turns and convert the fitting threads to a pipe thread. Then run a 1/4" pipe plug into the hole until it gets snug. Don't worry about shavings- - - -they just fall into the exhaust port and get blown away the next time the engine starts. You can use brass or steel pipe plugs, and if you want a clean-looking installation, use Allen socket plugs instead of the square-headed type.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!