Front heater core, what is the book time to replace?

I am having a hard time getting the dash out almost got it but something is holding and would like to hear some sugestions?

The heater core mission. As for discharging the A/C system, I would like to state for the record that it is not necessary to discharge the A/C system to exchange the Heater core on an 98 Expedition/Navigator, just drain the coolant, remove the dash, open up the box that house the A/C system core and the Heater core, remove and inspect the blend door for cracks where it attaches to the actuator, check the blend door actuator then cut the metal lines on the top of the heater core off for easy removal, from the engine compartment pull the heater core lines through the firewall for easy disconnect and that is it, you are now ready to start the re-install process. One thing I recommend is while you have everything apart change the blend door actuator, especially if you see traces of where the coolant was leaking in the box. 9 out of 10 times the coolant leaked out through the actuator and it is just a matter of time before the electrical circuitry in the actuator quits working leaving you with no heat or only heat. Well moving on to other issues now that heat works and spring is near. Good luck and install in reverse, take pictures with your cell phone to use as reverence on things you took apart and Merry Christmas.