Plugs for flare fittings?

[Robert W. Hughes]

Before you rush out and buy pipe plugs you might want to check this: All
of the GM AIR systems I have seen use 1/4inch inverted flare fittings on
the exhaust manifold. Steel plugs like this are not too hard to find. If
the tube that goes to the manifold has a flared end with a nut behind it
that turns on the tubing it will probably be one of these and not a pipe
thread.
-- 
Robert W. Hughes (Bob)
BackYard Engineering
Houston, Texas
rwhughe at hal-pc.org