I just went through the painful replacement of my heater core in My 442. It actually wasn't as bad as i would have thought. Now i am in need of the flexible ducting as mine are dry rotted. Right now i have used gorilla tape to at least put them back together. I would like to know where i can buy quality replacement duct work.

 

I bought some (4") for my forced air from these guys...they have all sorts of sizes and they sell it by the foot. http://www.aircraftspruce.com/catalog/appages/cat.php

 

The Parts Place and Old Air Products carry the original cloth/ wire style of duct hose for your dash.

http://www.thepartsplaceinc.com/ocat...&YearList=1970

http://www.oldairproducts.com/catalog/