I'm planning on taking the lower shelf out of my SX4 too, just to simplify and clean up the interior. I'm still working on the motor, so I haven't gotten to the interior yet. Check out idahosx4's Eagle . He has AC without the shelf. Looks like he used some different lower vents that attach under the dash. I imagine you would just run the ducting to wherever you need. He has a recent post, "My 81 SX/4 Project with 4.0 Swap," in the project cars section with a link to a photo album. Doesn't talk about the shelf delete, but you can see it in the pictures.