I was under the inmpression all the Stato/Caprice had trizone HVAC.
Either way the HVAC already has the duct there but it’s blanked off. There won’t be any internal doors for airflow control.
If you wanted it, you need to change the HVAC and that is a fkn massive job. Most of the car seems to be built around it. Degas the AC. Then the control module needs to be changed to trizone as well. You may need a different head unit that has the trizone features? I’m not certain on that though. You might need the BCM to be tinkered with using a Tech2 so it works as it should. Again those details I’m not certain on but would be realistically something to plan for.
If you feel there’s not enough air, the ducts leading to the back leak a lot of air on the way there. You could remove the centre console and then the ducts. Re seal all the ducts with tight fitting EPDM foam from Clark rubber. Don’t use the crap light foam the factory use. I insulated them as well where possible. Used foam/butyl sound deadener. $35. No air leaks out now and the flow to the back is greatly increased. I’ve done two VZ’s and one Calais like that. Makes a difference.
