Heater Hose Connection

[Fairlane500]

Have a 2bbl. 292 engine.  Aquirred 4bb. manifold  to replace 2bbl.  Looking at the heater hose fitting I'm finding two styles.  One has an extension beyond the threaded portion the other does not.  Do not know why the difference or which is correct for my application.  Does anyone know why the difference and which would be the correct one for mw 57 Fairlane 292.  Thanks
.

[lalessi1]

I looked in the parts book and as far as I can tell there appears to be two different ones B7A 18599-A and B7A 18599-B. The latter is for cars with A/C. Here is a shot from the parts book and a catalog picture from Concours Parts for reference.

[Fairlane500]

Thanks lalessi1, the heater connection with the extension appears to be the correct one.  Still don't understand the extension.  Went to Prestige Thunderbirds here in Whittier  (Thunderbird Restoration) and they use the one with the extension as well.  I think I have the answer for now thanks.

[cokefirst]

That heater connection is not used on the Thunderbird.  The Thunderbird had the vacuum operated heater control valve on in that location. 

[SkylinerRon]

That's for a 58 up T-Bird not 55-57.

Ron.