Thanks so much for your input, Mike & Brian
Window rattle: Currently using thin strips of cardboard cut from Corona 12 packs. Very natty—ratty! Quieting the windows improves the experience a lot!
Suspension: Does anyone know the part number for a ball joint? Is it: 40110-16501 (ebay has one). Edit: I see this discussion that the part number is different.
Suspension: Would these Sears shocks affect the stance of my slightly lowered vehicle?
Fumes: Heater was repaired, so more evidence that the drain lines might not be intact
Fumes: I'll check manifold condition (supposedly it was repaired)
Fumes: I'll check the seal between the header/exhaust/pre-muffler. I have a custom setup, so there may be issues when it was reattached.
Fumes & Backfire: exhaust leak pulling in air causing backfire may also point to manifold repair.
Backfire: RaceNeely also says to check the cleanliness of the fuel tank and lines
Mike Young, Roadster master mechanic lives in my neighborhood, he's going to look at the backfire issue tomorrow. Could also be a source for gears Brian suggested. He definitely has a 5 speed (nice!).
Brian, thanks for the offer of looking at my 'Bird. Let's set something up.
Mike, hope to be at JCCS this year. Hope you had fun on your recent trip to Japan!