1978 F250 SCAB CS, factory air with integrated controls

I've looked, but can't find the info I seek. Bought a replacement driver side flexible duct, but the end that connects to the plenum is round, and smaller than the one on the mouse bathroom I removed from the truck. That one is larger and oval shaped, as is the outlet on the plenum for said vent.

Did I get shipped to me one for the other factory air setup? There were different ducts for the different factory air setups?

 

Below is the flexible duct that's for the factory installed A/C, square on one end, round on the other.
Starting in 1978 Ford also used a hard duct that got rid of the flexible piece.
Look at the pictures of the blue truck, do your vent inlet and plenum outlet match that? If they do, then you originally had the hard duct.
The hard duct was most often found on the full size Bronco but it was also used on the trucks.

 

Thanks, Mike. Blue truck pic - where that piece of flex for the hard duct attaches to the plenum looks like the vertical oval that is on my plenum, but my old flexible duct fit on it, and the new one won't. In the pic I attached, my old one is on the left, new old one on the right. Note size and shape differences. Guess I'll fab an adapter, but I was just curious as there seems to be two different LH ducts for factory integrated air. Maybe NumberDummy will chime in as well...

Edit: ok, the pic loaded sideways, so now old one is on the bottom

 

Well maybe this will help? Looks like you got sent the wrong duct...

Thanks mikeo0o0o0 or ND for the diagrams.

 

Here's another pic to add to your collection.

1973/75 F100/350 with factory installed integral A/C:

 

Fantastic, peeps! Looks like my 1978 F has the ac from a 1978 Bronco. Y'all are great, thanks.

 

I still don't understand how my old flex is sized to fit the "hard duct plenum". It's moot - I either replace or adapt, but I like learning things. Old flex doesn't appear altered. Oh, well. Doesn't change what needs to be done.

Thanks again, folks!

 

Hmmmm.....but either part can attach to 18471? Same plenum in both pics. Am I missing something?

 

18471 is the "basic" part number.

You would need to go to the text portion of the parts book to get the proper suffix and prefix for your application. That is where the different part numbers for different applications will show up.

 

That 'splains it! Thanks.