My '67 Ambassador lived much of its life in Alaska before I bought it in
South Carolina. The original AC had been removed years ago and the roof
patched inside and out with a large sheet of aluminum. I bought a new
Carrier unit and pulled the big patches off the roof. I discovered that the
original AC had separate units for the condensor and the evaporator like a
home central system. Nothing went through the roof but the refrigeration
tubes and some wiring. The new units have condensor/evaporator in one unit
and blow conditioned air into the trailer, therefore they need a larger hole
than the original did. A template was furnished with the new unit and the
hole specified fit nicely between the top bows of my trailer......the
original power cable was still in position and functional, too. Took me
about a days work to install. The hardest thing was cutting out the hole on
the inside with the aluminum chips raining down on me. Everything's cool
now, though.........and when I'm not travelling in my trailer, I can use it
to hang meat.
Beekman