Need to add air conditioning.

If you do go with a Classic system, check out this guy's website. He made some mods that i did to mine. Check how he flipped the firewall plate. I did this mod, but the holes have to be dremmeled out, and the rubber grommets custome fit. It turned out ok for me.
http://www.cardomain.com/ride/2400202/4

just a thought if you are ok with spending a little more money not a ton you can check this out over at classic auto air. Personaly i would save the original unit because my personal opinion i like the original look alot more than the aftermarket ones. but check this out and give it some thought. They will rebuild it (im sure you could find a cheaper price if you tried) and they have conversion kits. I am sure you will need some more parts im not sure but check it out http://www.classicautoair.com/Ford-Factory.asp

I think he later took it back out, or moved the switch or something. I couldn't drill through my new bezel anyway...so i skipped that part.
I also made a could other mods. THe upgraded a couple things in my kit but not the other parts. Like the wires that attach to the new fan switch, show in the instructions to be several individual wires, but I got a unified plug connecter thing so it was more like a harness. And that left some other short extension wire included unused. No big deal. I also changed the wiring for the preassure switch. THey give you a rubber boot with two long white wires coming out of it. I pried the brass connectors off the white wires and put the blue wire through the boot that comes from inside the car going to the preassure switch and crippmed and soldered the connector back on, then ran a long black wire in the other side and crimped and soldered the connector on that. Way better looking than crimping a bunch of wires together to strap under the shock tower brace. Ran the new black wire through the factory harness hangers, down to the alt, up behind and accross the intake to the compressor clutch. Looks much cleaner like that. You'll see when you get to that.

I've been told the evaporater in the factory unit is not very effecient, but I think they can rebuild it like posted above with a modern evaporater. That would look like original, other than the compressor and would run R-134a.

Thanks for the favorable comments on the write up and install. This was done on a 6 cylinder car. I am planning a few more changes when the V8 goes in.
1). Use the ford drain hose and go through the tunnel instead of the firewall.
2). turn all hoses 90* towards the drivers side, and fabricate a C.F. cover that fastens to the top two bolts and lower passenger side bolt. This will cover the heater valve and fittings, and help hide the hoses & wiring that will run behind the engine
3). Find or fabricate the 3 speed fan switch + pushbutton. My goal is to have the fan switch also activate the A/C compressor.
I did move the added switch. The light is still in place, and for me useful. The pushbutton, and light are really only needed for the convertible. Coupe and Fastback, don't really need the A/C output at floor level as strong, and the door switch is pretty adjustable. Definitely enough for a top up car.
I am also looking to add a rear window defogger with a glass rear window, so that may influence the switch/light situation. The bezel is pretty scratched up, so I had no problems drilling a hole. Now when I get the new bezel, I may look for a different way.

BTW: The original Ford under-dash system can be made to really put out some cold air with R134a. It requires a different expansion valve, and benefits from an R134a spec condensor.
Good luck with your project!

I couldn't find it on their website, but I'm pretty sure Classic Auto Air makes a 6 channel factory replacement condenser that's more efficient than the original or standard replacement 3 channel design. It's available through NPD and critical IMO if you're switching to R134A. Since your car was a factory AC car, and you already have all of the under dash pieces, I would do as spade 33 suggested and send the entire plenum out for rebuild. Then you can replace the AC hoses, condenser, dryer and expansion valve with all new repro stuff, and it will use the factory routing and install locations. To finish the modernization, use a mid 80s Ford compressor from an F150 with a 302/351W rotated 90* on it's side. The factory discharge hose will hook right up. A factory replacement sight glass hose will go from the dryer to the firewall with the original routing. Now the 2 critical parts to this upgrade are fabricating a mount for the compressor and making an adapter for the suction hose that goes to the condenser. The mount is really not that hard. Use 3 pieces of flat plate, 2 identical pieces with holes to mount the compressor, and slots in the bottom piece that will mount to the factory bracket that bolts to the head. After you have everything lined up so that belt aligns properly, tack weld nuts in place on the bottom of your fabricated AC compressor bracket. You can use either R12 (replacement) or R134A.

Just a bit of useless trivia (that I can't confirm btw) I was told by a retired factory York distributor that all of the York and Tecumseh automotive compressors were actually made in Japan. Because WWII was still fresh in everyone's mind, The American Auto manufacturers couldn't install a Japanese sourced component in the early 60's, so they went through York and Tecumseh, who spec'd them for American cars and put their names on them.

Classic auto air makes two versions. 1) like original with either R134 or R12, 2) A complete in dash unit that utilizes you controls but eliminates the under dash evaporator. A third option is to have them rebuild your evaporator and supply a kit to convert to R134 with a Sanden compressor. WE've done the 3rd option and are currently doing # 2. the only problem is with #2, it is for a vehicle that was not equiped with AC. We'r blocking off the original holes for the hoses. this kit does send a hose around the driver side back to the firewall and behind the engine to the dryer. this system also has dehumidified air for the windshield defrosters.

Thats too cool. Might as well tell everyone...

Upgrades for R134a

Sweet!
That's a very nice piece!
Are you going to change the condensor and expansion valve so you can run R134a while you're at it?
A few years back, I went down there and met with the guys at C.A.A. before I bought the kit for my '66. Good group with some deep background (all the way back to the early A.R.A. days!).
Living in Arkansas, you may want to run a good fan shroud and fan assembly with the new Griffin once you get the A/C fixed.
It seem's I'm doing a good job of helping you spend money. Sorry man! Well at least it's money well spent!

If it makes it any better, I just dropped $400.00 on sheetmetal to swap in a Griffin radiator for a '68 into the '66. Good grief!