Whistling Classic

[Brad Richards]

Hi All,

I put a HotShot header on my '93 a few months back, and have had an
annoying vacuum leak ever since.  At least I'm assuming it's a vacuum
leak -- it acts and sounds like one.  It only happens under pretty
significant load, so I can't just stick my head under the hood and
see where it's coming from.

The install went very smoothly, and all the emissions bits went back
on properly.  I've been over it multiple times and can't find any
loose or missing plumbing.  When getting the EGR fitting out of the
old manifold, I had to loosen the bolts on the intake  end of the EGR
pipe to get enough play, but they're bolted back tight again.

Is there some likely place to look, given that I only hear the
whistle under significant load?  Anybody else have this problem after
a header install?  The pitch of the whistle is almost speed
independent -- it rises in pitch slightly, but it's much more
dependent on load than engine speed, so I doubt it's a belt or pully
or some such.

Thanks,

Brad Richards