On my '54 AirFlow heater, 1-3/4 ID cloth hose fit over both outlet ports of the defroster at the heater and over the passenger duct. The hose fit INSIDE the driver duct. I believe (?) that I have seen pics of a rubber collar that secures the hoses, but I'm not sure. Collars are not mentioned in the '51 and '54 Accessories Installation Manual.

EDIT - - - I just checked the Accessories Manual again:
> The '51 Manual does not mention collars or bushings.
> The '54 Manual has the same instructions as the '51 Manual, but modified the diagram by adding an arrow to both ends of the drivers hose with the word "BUSHING". Don't know if a bushing was also used with the passenger side. Wonder if the drivers hose was 2" ID?

FWIW - I purchased cloth hose from Chevs of the 40's. It is sold in 36" sections. I needed a little less than three feet of hose to the driver's vent, but needed more than the remainder for the passenger vent. So I used the old plastic hose that was on the truck when I bought it for the passenger vent. PO secured the hoses with duct tape. I didn't secure the hoses. The drivers cloth hose has stayed in place. The plastic hose came loose from the passenger vent. I jammed it back on. May need to secure. Don't know if plastic vs. cloth contributed to it coming loose. I've only used the defroster once, so I don't know if continued use at "heater temp" will cause them to blow off.

Congrats on being able to see the finish line on your restoration!

- Lonnie
My '54 3104
Photos that I have shared on Stovebolt via PhotoBucket are no longer available. Please contact me if you want a photo from an old post.
lonniecook [at] aol [dot] com. I sold my '54 3104 12/12/2017, but I still visit Stovebolt.

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