The design of the inlet hose isn't exactly one of the General's better ideas.
1st, do NOT simply loosen the hose clamp at the heater core fitting next to the firewall and start yanking. THIS will almost guarantee a ruined heater core where the tube is fastened to the core itself. (IF that happens, then you have the "fun" job of replacing the heater core also.)
I usually slit the hose length wise on the fitting then GENTLY peel the hose from the fitting.
The other end of the hose (engine end) is the design I don't care for.
The ones I've done I have simply taken the stock fitting completely off and replaced it with a standard hose fitting like the one shown here; Murray Climate Control Heater Fitting
NOTE; This may NOT be the exact fitting you need but it gives you an idea of what too look for.
After you get the fitting changed out it's a simple matter of installing the hose and tightening the hose clamps. I usually spritz a little WD40 on the inside of the hose ends to make installation easier.
This method is not only cheaper, but it eliminates the goofy fitting that was installed from the factory.
Hope this helps.