JS,

Pictures of what the guy is talking about:
Preheater shroud- http://www.dykstra.cc/1969Firebird/10-16-03/IM001376.JPG Where was Bjorn when I was searching for four months for a correct 1969 preheater shroud that no one repro's???

You can see from this picture where the hot air tube fits into the aircleaner even though the preheater isn't on the engine in the pic:
http://www.dykstra.cc/1969Firebird/10-16-03/PA160025.JPG

Here is a picture showing the entire system:
http://www.dykstra.cc/1969Firebird/10-16-03/MVC-006F.JPG

I'd be surprised if you couldn't just go to a different testing facility and pass with no problems...sounds like the guy you got had a little extra knowledge that he was proud of.

But, I'm an originality buff so if you want my opinion ( you don't ) you should put it all back to original because it looks so much better