1955 Ford Thunderbird heater duct question.

[37 Coupe]

My 1955 Ford Thunderbird came from a Thunderbird and '55 Fairlane restorer/collector and some loose parts that came with it are different. My question is the chassis parts books calls out different numbers for TBird and Fairlane heater duct #.So I have one that is about 7" tall and the other is almost 8" tall anyone know if one is TBird and if they would both work? Thank You

 

[Hot Rod Reverend]

They will not work/swap from what I understand. In your photo, the one the right is for the passenger car.

 

[paul2748]

The one on the left looks like the T Bird duct attached to the firewall in the engine compartment. The other one will not fit a Tbird as far as I know and being shorter the flex piece for a Tbird is not long enough to reach the metal duct in front of it..

 

[dmsfrr]

I have three of them. One from/for a generally original '57 Bird with at least 3 previous owners.
One in a '55 Bird of fairly questionable origin. And another from an ebay vendor, advertised as a used '55/'57 T-Bird part.

All three are the same height, 7 inches, and appear to be the same.
They fit in the 2 Birds without any trouble.

As shown on the right side of your photo... all three have the 'flat' not perpendicular style seam holding the upper & lower half's together.
On all three, the small rectangular neck for the flex duct is approx 5/8 to 3/4 inch in length. Not what appears to be approx 1 & 1/2(+) inches on your example on the left.
.