Classic Auto Air - Air Conditioning & Heating for 70’s & Older Cars & Trucks.
Classic Air is what I have used in a Bentley.
I've not seen an integrated dash air con system put on a 409.
My system is in the boot and discharges cold air from pods on the parcel shelf.
I wouldn't do that again and would go for a front mounted underdash unit but couldn't find anything which didn't detract from the beauty of the dashboard.
You may have the same problem with the 409, 2 of which I've owned.