doogie67,
In my opinion, the downside with all of the aftermarket setups is that when installing they require blocking off the passenger side air vent which in effect gives you no fresh/outside air option. As a smoker, I'm a big fan of fresh as opposed to recirculating, not to mention it just feels more comfortable & natural to me. That being said, I know some folks who really like the Vintage Air stuff and some others that have had good luck with Classic Auto Air. Both setups have their own plusses & minuses, but both companies are reputed to have very good customer/product support. Personally, I think the best way to go is to find an OEM heater/AC box and control panel, refurb with new seals, etc, new heater core, upgrade the evaporator core with a new, modern high efficiency evaporator, new Sanden compressor, new high efficiency condenser and new hoses. In the end you'll likely spend similar $$$, but have the best of both worlds. Here's a link to a good vendor for
condensers/hoses/compressors/parts:
Aftermarket Air Conditioning For Automobiles and AC parts
Their complete kits don't look bad either, but I don't know anyone who has used them. I live in Las Vegas with a lot of 115+ degree days and am in the process of the upgrade I suggested. If you can wait for a full report on how well it works, I should be done in a week or so. My car is a 68 which is a little different but still basically similar components.
Just My $.02, or Maybe $.03,
Gene