The measurements made on my 67 Barracuda (w/o A/C)
21" Hose fits over 2" nozzle by floor.
25" Hose fits over 2.25" nozzle by floor.

Both hoses have 2.57 i.d. at the outlet end. The defroster grill connections measure 2.5" OD.

One of my surviving ducts has a snap lock which I've seen on some, but not all photos purporting to be NOS or original hoses.

I call them ducts (the term usually used in HVAC for air carrying) but the 67 Chrysler parts book calls them hoses.

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