Heater Box - Input Wanted

I'm not sure if a 64 and 66 are the same. And mine is a factory air box. I just did it not long ago and I'm trying to remember.

I pulled the glove box to get to the electrical connectors and cables. There is a nut on the top left of the box.

Also on the firewall, I think there was a couple of nuts towards the center that had to come out. One, for sure.

That's all I can think of.