So how did your heater repair work?
I'm curious as I have a 64 Falcon and the heater box became detached from the cowl which I assume led to some flexing and leaking in the heater core. All I know is that if I tried using the defroster I got a lot of steam on my windshield. As a quick temporary fix, I just removed the heater box and replumbed the heater hose to be just a loop.
Haven't even opened up the heater box yet to see if I can determine the problem with the heater core, which was supposed to have been new when I bought the car.
In any case I'll also need to reattach the heater box to the cowl and any tips or advice you have would be appreciated.