I am attempting to remove the heater from a 1972, 142. I have followed Haynes guide to remove the four bolts holding the heater housing. I have the heater hoses cut (have new ones to replace them) and I removed the clips from the bottom where the white housing connects to the heat distribution system.

I see there are clips on the top of the white housing as well. Then there is black plastic the fits up into the firewall and dashboard areas. I assume this it the circulating fan area. Do I need to remove the upper clips to get the unit out?

I removed the glove box as that seems to be the area where I can slide the heater unit to remove it.

Suggestions here would be very helpful.