Technical Anyone have a Tri5 BOP with the under seat heater

I am tying to restore the under seat heater in my 1956 Pontiac wagon to working order but I cant find the oval flexible air duct that connects the heater box to the duct work. Anybody out there solve this problem yet. Thanks

 

My underseat heater doesn't have duct work. It just blows forward and rear. Under the hood I couldn't find that flex hose stuff so I just used a dyer duct from the hardware store. Not correct, but it works.

 

I'm not sure if one of the Pontiac restoration suppliers carries them and I'm trying to recall their size but I wonder if you could possibly use a section of tire tube as a substitute?

 

I removed all that stuff from a Buick not too long ago...........I'll check to see if we still have it, it is a very low mile car and everything is in great condition. PM me to remind me!