Where to get 1968 C10 inside cab heater duct hose

[HeavyHauler]

Well I noticed today on my 1968 C10 that the inside under dash heater duct defroster vent hoses are oval shaped at the top of dash vent windshield area but the other end that goes to the under dash heater box is round.

Where can I get these special heater duct hoses at? I looked at the Classic Parts of America website and it shows heater duct hoses that are round on both ends.


If the heater duct hose end is round does it just still slip over the oval dash defroster vent?