Steve Baur
Former Editor, Modified Mustangs & Fords
July 11, 2014

Save for a few areas of the country, the weather reports these days are full of abnormal temperature swings. Whether or not that has anything to do with global warming is an argument best left to others, however you can regulate the temperature in your car by installing an aftermarket heating, ventilation, and cooling (HVAC) system.

Classic Auto Air has been servicing the classic car industry for years, and when we came across a restomod Mustang in need of some conditioned air, we called Classic and ordered one of the company's Perfect Fit Elite systems.

The model-specific Perfect Fit Elite system for '67-'68 Mustangs/Cougars is a retrofit kit that allows you to control a modern HVAC system with your stock heater or air-conditioning controls. Your factory controls and the vents from which the air flows, however, are the only stock components you'll be using. The company's EZ Cable integrators, EZ Wire system, and included ECU turns the factory ventilation into a fully electric system with endless adjustability.

While the Perfect Fit Elite systems are designed to bolt in to your particular application with minimal modification, sometimes living in our world of Modified Mustangs & Fords will offer challenges, like and engine combination that is a bit outside the typical small-block Mustang. Such was the case with our subject restomod coupe, which currently sports a 4.6-liter, Two-Valve V-8 engine. The engine itself wasn't necessarily the issue, but the location of the A/C compressor down low on the passenger side was—the stock small-block location is up top on the driver side of the engine.

Not to worry, though, as Classic knows this can often be the case with project cars, and the company can offer you a myriad of options when it comes time to order. For the most part, all we did was ask for the hoses and the ends to be unassembled, as we would need to reroute them for the new configuration. We skipped on the compressor as well and picked up our own that was specific to the engine.

We were very impressed with the easy-to-follow instructions included with the system. More than just a step-by-step instruction manual, the Perfect Fit directions also tell you what components are in each bag—there are a number of bags and they are all marked with simple letter designations. As long as you keep everything in the bags until needed, the whole process is simplified and broken down into easy steps. While our custom installation did require a few odd tools to complete the modifications, installing the Perfect Fit system on a stock vehicle requires only basic handtools.

Classic Auto Air spent a great deal of effort engineering it's Perfect Fit systems, focusing on quality over low-cost with regard to the included components—an OE quality with better-than-original performance and reliability was the ultimate goal.

The bulk of this installation was completed at Gillis Performance Restorations (GPR) in Port Richey, Florida, where proprietor Rusty Gillis has been slowly working on his own restomod coupe—our subject vehicle. Once Brian Gillis of GPR had installed the major components of the system, we brought the coupe down to Custom AC Solutions in Tampa, Florida, to have the new lines fit, cut, crimped, and installed.

We've worked with Custom A/C Solutions' Walt Cunningham and Antwaine Christopher before and they're always ready with a custom solution for sure. Our project was quite simple in comparison to some of the company's other current projects, and we were done with the line installation in just a few hours. We also need to give a shout out to Mark and Tim at Classic Auto Air's Factory Original A/C Parts and Restoration Services division in Tampa, Florida, as they were able to hook us up with some fittings and a custom metal condenser line for our project.

Though the kit ships in a sizeable box, the installation of the Perfect Fit Elite Mustang system was fairly straightforward, even with the custom modifications that we needed to make because of our late-model Modular engine. It's bad enough that you have to bake in the sun all day at the car show, or in traffic on your way to work. Keep yourself cool (or warm) and arrive in comfort by adding aftermarket air conditioning to your ride. It'll likely be one of the best mods you make!

01. The Classic Auto Air Perfect Fit Elite air conditioning kit for ’67-’68 Mustangs/Cougars retails for $1,479 and includes all interior components, evaporator assembly, condenser kit, pre-crimped hoses, Sanden-style compressor, high/low pressure switch, aluminum hook up tubes, compressor mounting hardware, installation instructions and a mounting template.

02. Our first order of business was to cut an opening in the freshly smoothed firewall of our restomod. Long ago, air conditioning wasn’t in the plans for this coupe, but that has since changed. We didn’t have the original blower motor hole for reference, but GPR’s Brian Gillis was able to use the included template to locate it from inside the car. We then moved the hole’s location 2 inches to the right to clear the cylinder head/cam cover.

03. In getting started, it’ll be really helpful if you remove the radio and glovebox if it is currently in the car. The HVAC unit is test fit to ensure that we had clearance for the windshield wiper arms under the dash. Once the final position was established, we could then mark where the drain tube would exit through the firewall, remove the box, and drill.

04. The box is held in place by a number of included brackets. Pay special attention to the diagram in the instruction booklet. Though there are pilot marks on the right side of the case, you only use the ones on the far left.

05. The front part of the box that faces the firewall should be angled downward to promote the exit of condensation inside the box through the firewall drain. A clear plastic drain tube is included in the kit; you may need to make provisions in the engine bay to direct the water drain from dripping right on the exhaust.

06. In the engine bay, it’s time to seal up the area around the HVAC lines, and the kit comes with this plastic plate. It’s a tight fit getting all four lines, plus the water valve wiring, through the plate as it has a foam insulator on the backside. Once we found out that the plate would not cover the hole we made, we simply flipped it upside down, opened up one of the holes to allow the bigger line to go through it, and then fastened it to the firewall for a perfect fit. Classic includes refrigeration tape to seal up any gaps around the pipes.

07. It’s time to mount the control module now, and we fastened ours right to the underside of the cowl since it is sealed off from the elements top side. The EZ wiring kit makes connecting the components super easy, as everything is color-coded.

08. Moving on to the duct work, you’ll find two panels in the bags; one is for the defroster vents, and the other is for the dash vents. The dash vent panel just uses press-on clips to secure it, while the defroster panel utilizes a combination of clips and screws.

09. To install the included center vent panel, you’ll need to remove the nuts from the back side of the trim panel and remove it. Then, follow the diagram on the instructions to excise the required dash metal to make room for the dash vent panel.

10. Once the vents are in, the gauge cluster and dash panel on the opposite side hold it into place. You’ll want to keep a firm hand on the vents when you attach the duct hoses to it, however.

11. To connect the duct hoses to the defrost vents, you’ll need to slide these included adaptors on.

12. The lower dash vents bolt right up in the corners using the included hardware.

13. It’s a bit crowded behind the dash once you start running the duct work in there. Just be sure to start with the defrost lines first, followed by the forward vents.

14. Moving on to the factory slide controls, we have to attach the cable converters to the slide controls. You can pick and choose which lever you want to do what. We have the Temp controlling the hot/cold, and the Heat controlling the vents. The Defrost is just along for the ride.

15. Secure the cable converters using the included push nuts or China caps as they are sometimes referred to.

16. The blower speed switch is removed and replaced with a new one. You’ll need to attach this adaptor bracket to mount it. Just slide it down and screw it to the switch panel frame, then bolt the switch to it. You may need to tweak the angle of the switch lever to make sure it does not rub the bezel during operation.

17. Here’s a quick FYI, as it can be easy to do when moving through the install. Make sure the cable converter loop at the end wraps over top of the lever rather than underneath like the one in the foreground. Having it underneath puts unnecessary strain on the cable.

18. Moving back into the engine bay, we installed the condenser, but flipped it to face the passenger side of the car where the compressor is located. While doing this would cut down on the length of hoses needed to connect it, it did prove problematic when trying to mount the dryer, as the core support does not have the extra space for it on that side. To solve that and clean up the behind-the-grille area, we decided to mount the dryer behind the radiator core support.

19. The condenser is secured to the core support at the top and the bottom. Here, you can see that we needed to clearance the front fascia so that the lower refrigerant line could pass by unobstructed.

20. And speaking of the lower line, we had this custom aluminum line bent up to connect the condenser to the dryer. Walt Cunningham of Custom AC Solutions keeps a spool of special wire around just for mock up purposes like this. Then he can take the bent up wire and have the line bent up for him as needed.

21. Here you can see the placement of the dryer below the coolant overflow tank and air-filter assembly. It was simply attached to the lower portion of the fender apron, which put it on a direct path to the HVAC box.

22. Car owner, Rusty Gillis, popped for a new compressor for the 4.6-liter Thunderbird powerplant. He also had presence of mind to hold onto the manifold that allows attachment of the refrigerant lines, as well as the fittings from the old lines.

23. We reused the old fittings, although this particular one was modified to match the size of the hose to the size of the pipe on the manifold.

24. We contemplated a number of routings when it came time to connect the top of the condenser to the manifold. We opted to make a hole in the radiator support and run the line straight out of the condenser. Once tucked inside the core support, it loops around to the manifold.

25. Here you can see we have all of the hoses mocked up prior to clamping the fittings on to the hoses. When routing the hoses, Cunningham recommends working with the natural bend of the hose rather than trying to fight it.

26. Our connections at the HVAC box are made, and in this photo, Cunningham has installed a T fitting on the left line that includes a port for the pressure switch. Said switch has been rotated to face downwards, placing it virtually out of sight.

27. Here you can see the final placement of our custom hoses. It’s clean and you likely won’t notice them at all once we get to installing the speed parts on the top side of the engine.