The problem with changing the core out is that all the bolts have to be removed frome the cover. they go all the way around and there are several behind the pass fender. the manual says to loosen the fender from the rocker panel and hold it out with a piece of wood. once you get the cover off, there are clips that hold the core inplace. those clips are not really accessible from inside. iIf you try it from the inside you still have to remove all the cover bolts then remove the glove box, remove all the vents and all the cables that go to the heater control. the heater control thing is a real pain. the biggest problem with the hole thing is that the blower motor is just in a bad spot. 60s engineering!!!!