heater core

I think you'll find those aftermarket defroster hoses are the wrong diameter on at least one end. Good info here....all I can add is to remove the rectangle plate around the heater core pipes in the engine compartment to give you a little extra clearence and to take care pulling the heater suitcase away from the firewall so you don't accidentally damage the firewall insulation or break the back of the glove box insert. You may also want to remove the RH kick panel. If you have any removeable floor mats or carpet, take them out of the way for extra floor to dash clearence and lay an old towel down so anything leaking (usually rusty/nasty) from the old core doesn't stain your carpet. Also, take care removing the clips holding both halves of the housing together so you don't chip off the edges. A little lube helps on those.