Go to your local Napa Dealer and ask for the 2" and 2.5" heater box hose. Its sold in 6ft lengths so you will have to cut it to proper length but is much cheaper, installs much easier and looks very correct for Mopar A-bodies. I bought the DMT kit and it didn't fit well at all. Here's some pics of the DMT kit. As you can see, its impossible to slide the hoses over the heater box outlets with the Adapters in place as both hoses I received were the same diameter. Note: I was installing the DMT kit on a 68 Cuda. Not sure but I believe the heater box is the same as your Demon.
Here are pics I took of the DMT kit I tried to install as well as pics of what the originals looked like installed. Note the clearance differences between the originals when installed vs the DMT hoses. Its impossible to install both DMT hoses at the heater outlet the same time.
Note: I contacted DMT and they did give me a partial refund . I have dealt with this company for most of my gaskets and insulation products and with this exception, they have been first rate and very good to deal with!!