defroster duct work

You already have things covered but here's what I did years ago...

I ordered some 2“ and 2.5” duct hose from Nostalgic Air Parts who sells hose by the foot along with their 2” to 2.5” adaptor. I attached a piece of 2.5” directly to one of the ducts in the dash. I then attached a short piece of 2.5” hose to the other duct, followed by the reducer, and then the length of 2” hose. If you look closely at the left hose above you can see it.
The nice thing is, the 2” hose fits on the heater box outlet snugly, and the 2.5” hose fits the slightly smaller outlet with enough interference that it would probably stay on by itself. A zip tie will secure it for sure.

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