Bob's right on on his last comment about the recirculation of the cab air. If you can make it work, it will be a neat setup.

Everybody has their own vision for their project, which is what makes rodding so great. Personally, I tend to go for a nostalgia look if it can be pulled of well. My plans for my 37 Dodge PU are to use a nice 50s vintage under the dash AC unit with a rather unusual chrome face and built in thermometer. The heater will be a vintage fire wall mounted unit with the three individual doors (which I will send out to be chromed) it also has the defroster vents that can be plumbed into the existing dash vents (Which may be a problem for you with the under seat installation.