I found some duct. Auto Zone was able to get it for me, but I had to do the homework for them. You know how it goes, all they know how to do is to look up your vehicle and if their computer don't show what you need, you're out of luck. Ask for Dorman/Motormite 96004. It's 72" of 2.5" hose for a very reasonable $12 including tax. It looks like a standard non-AC truck (1977) would use 12", whereas mine has an aftermarket AC unit. It looks like I'll use all 6 feet. And best of all, it's made in USA.