Installing the Classic Auto Air "Perfect Fit" kit.

Most people ask "why A/C in a convertible?". When the top is down and the sun is blaring down on you, A/C is a must. The key to A/C in a convertible is to get it blowing from down at the foot level. Otherwise the air will just blow right out of the car without cooling you down.
The "Perfect Fit" kit from Classic Auto Air is the "perfect" answer for this. With one extra switch, you can set up the air flow to be infinitely adjustable between the dash vents and the floor outlets.
I chose Classic Auto Air over the other kits because of their design on the Evap/Heater core box, the way all the hoses are in the engine compartment instead of inside the passenger compartment, and the flexibility of setup.
As good as this kit is right out of the box, there are a few things that can be improved upon. That is what I will focus on here. The instructions are plenty good for even the most novice of home mechanics to follow. And after touring their facility, I feel they have a very knowledgeable and friendly staff, should you need support.

First modification was to rework the wiring, adding an additional switch, and a relay for the compressor clutch. Also the instructions have you cut the factory harness and pull it back through the firewall. I was not about to cut up the factory harness, it is not necessary, and would have taken more time.
Step one, add the switch to allow full air flow of air conditioned air out the floor vents.

I modified the fan switch so that it would push in against the SPST switch mounted to a bracket on the top. This switch wires in parallel to the defrost door switch. I also added a small red LED light to the front of the panel. This light comes on when the A/C is operating. I chose red as it does not affect your night vision. The light wires in parallel with the added switch.

Both parts came from radio shack.
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I have since moved the switch to under the dash, as the heater fan switch was rattling.
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Next wiring modification was to bring an extra wire out through the "heater delete" plate for the hot lead. I added a bullet connector and plugged it into the hot lead of the original heater fan wires. This eliminated the need to cut the harness and pull it through the firewall.
Last wiring modification was in regards to adding a 25A relay. The instructions have you bring the wire out and plug directly into the compressor clutch lead. This would mean all the amperage to pull in the compressor clutch is going to be carried by the switches. Instead, I opted to run this lead to the B+ coil lead of the relay, and run a fused lead from the B+ starter soleniod stud to the relay "Common", and then a lead from the "N.O." to the compressor clutch. Finally a ground lead with an eyelet that is secured on the same screw that holds the relay to the inner fender well.
Wired this way the total draw on any switch in the control circuit is about 1/3A. All the switches should last a very long time.

First mechanical change was in the way I mounted the "heater delete" plate. Here is how the instructions show you to mount it.

The plate is mounted on the engine side of the firewall with Two "Tek" screws. with no gromets to protect any of the lines. Kind of an ugly way to do things.
Here is the way I mounted it.

You can see I mounted it from the inside, installed gromets, and ran the wiring as well as the heater valve control cable out this point. It was a bit of work to get everything lined up correctly. The local Ace Hardware provided the correct Ford washered bolts. Installed this way allows the firewall to be cleaned up very nicely (this will get done when the V8 goes in).
The second mechanical change was in the way I ran the water drain hose. The kit includes a 6" piece of clear tubing. You drill a hole just above the brake line, and run this hose through. So sticking out your firewall is a clear piece of plastic tubing. I didn't think that was too cool, so I picked up a copper pipe elbow just large enough for the tube to fit in, and some black heat shrink tube that would slide over the elbow. I used Goop adhesive to glue the elbow onto the clear tubing, then ran the heat shrink tube over the elbow and shrunk it in place. While it was still hot, I squished the bottom so that water will drain out, and dirt, bugs, etc won't come in. Here is a picture of the finished product.

Next two modifications were to eliminate using Tek screws through the cowl. Here is a shot of the passenger side fresh air plate block off.

As you can see they install the Tek screws through the bottom of the cowl. This presents two fresh holes with plain steel screws, right where our cars have a tendancy to rust.
Instead, I used two round pieces of 1/2" styrofoam cut out to the size of the "hat" then glued them together for strength. Applied silicon calking, and pushed them all the way to the top, so no water would enter and stagnate. Just for insurance I ran a bead of calking around the inside lip.

The steel plate was going to be used as a mounting strap. It turned out not to be needed, and was removed.
The last place they use a tech screw is for the center evap box mount.

This would stick a screw out through the cowl almost center of the car where it would be visable by looking through the openings by the windshield wipers.
Instead I made a bracket that supports the box to the convertible (only) cowl cross brace. For a coupe or fastback, I'd make the bracket attach to the underside of the dash.

I also opted for 4 round underdash vents (ala the stock '67 configuration).

The last modification was to replace the kit fan with a 6 blade "Flex-a-lite" fan. This fan runs quieter, and even on 106 degree days the car does not get hot with the A/C on.

Everything else went as per instructions. Make sure to evacuate the system for at least 40 minutes. Don't open the receiver dryer until the last possible moment, and use straight refridgerant without any oil or leak detector. Your local A/C shop will have the proper test equipment to check for leaks.

The A/C works awesome, and is well hidden. Now on to dumping the old 3 speed gear box and install a nice 5 speed.

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