Even after searching, I haven't come across any threads about how to actually mate the old 3rd gen ducting (attatched the the firewall) to the 4th gen (attatched to the dash). One post said to cut it to match, but that's it. It's fairly straight forward, but I figured I would throw out a few of pictures to help someone if they wanted to see before they jumped into it.

This is the 4th gen ducting held up at an angle against the factory 3rd gen ducting. The 3rd gen is an 88 Camaro with A/C. The 4th gen is a 2000 with A/C:


This is the shape to cut the 4th gen heating duct. You can basically follow the fold in the plastic:


This is the 4th gen ducting held up to the 3rd gen after cutting the 4th gen to match the 3rd gen duct. As you can see, it's not an exact fit. I'd suggest closing this small gap off with some glued on foam or foam tape.


This shows where I would suggest you make some modifications. The bottom, larger piece of foam is blocking off excessive air from leaking out of the system. The 4th gen inlet is more narrow than the 3rd gen outlet. The upper, smaller piece of foam is preventing airflow from coming back out of that side since the openings there do not match up either. It's probably better to use some sort of tape or melt a cut to fit plastic sheet over the hole. Also, to match the openings you need to cut the 4th gen opening farther over. (Note the differences in locations in picture #1):

 

I cut the 4th gen to match but it still isn't completely right. Air blows out of the wrong passages or all of them at the same time. I'm planning on re-doing it someday by using heater duct-work or fabbing up something.

The reason 4th gen dash swaps are tuff is that there seems to be limited information on it.

 

Sounds like a vacuum pod/selector problem, but I can't really speak since mine isn't up and running yet. It'll be awhile for me. Still got lots of wiring to do and stuff. Jusdt figured some pictures would help if anyone wanted to see what was what.


-Bud

 

No, vacuum selector and hvac controls are correct. When cut to match, the vents on the thirdgen are not an exact match for the ports on the 4th gen. Thus, air goes into the wrong vents.