Under the dash surprisingly was not bad at all, certainly not a bear. I think most of the bolting was from under the hood and a few screws were under the dash.
I did make a video of the steps if you ever want to look before starting.
Have you looked at any specific units for under dash?
Curious what you may have found.
I did look (and bought) an under-dash a/c unit for the 78.
After receiving and test mounting, there was no way I could find for the evaporator to mount.
The smallest aftermarket evaporator unit I could find is around 11 inches deep and around 4 inches tall.
With the factory driver side heat duct still in place, no place for mounting exists. It would literally be in the floorboard area.
With the duct removed, there is only around 4 inches available under the dash - still not enough room, and there is no heat for the driver side floor.
I did not consider a heat - A/C combo unit. To be honest, I did not know there were any available "with heat".
Perhaps with all of the heating duct removed, more room may exists? Would they connect to the existing defrost for the windshield?
I decided to scrap the idea of a/c.
