I installed an Old Aire Hurricane AC/Heat unit in my '54 which already had a condenser and evaporator in it (though I installed a new evaporator, too).
You can see my install notes
Here I didn't use the under-the-dash plenum for the knobs ... instead I installed the controls in the bottom area of my dash and put '55 Chevy chrome knobs on them -- this gives a much cleaner look, I think!
I've had it 4 years now and have *no* complaints.
