On a 4th gen firebird dash, do i use the 3rd or 4th gen vent ductwork?

 

4thgen. Just have to do a little modding/cutting to where it mates up with whats left of the 3rdgen system.

 

get some of that black flex tubing from a hardware store . don't be surprised when you have to fabricate some parts . i used a few sheets and a couple of blocks of aluminum and just cut / grinded what i needed.......

1990 iroc L98 with 2000 camaro dash and console

 

I chose not to use any extra tubing etc. Check out the link in my sig I have pics on how I cut mine to fit like the 3rdgen one and it fits and seals perfect. either way you chose it will be fine.