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The Big Chill

Want a Cool Mid-Year? Here's How to Add a Bolt-In Air Conditioning System

Bob Wallace Aug 27, 2002

In an age where even the most basic econo-box comes from the factory with air conditioning, it is sometimes hard to recall a time when a Corvette with "factory air" was uncommon or unheard of. An air conditioned Corvette wasn't even offered until the 1963 model run, the first year of the second generation of Vettes, and factory air didn't become standard equipment on Corvettes until 1980.

Although the output of those early A/C systems were pretty anemic, and by today's standards they were primitive, the percentage of factory-air cars to overall production increased every year. In 1963 just 278 Sting Rays out of the 21,513 produced had air conditioning, a meager 1.29 percent. In 1967 3,788 of the 22,940 Corvettes built (16.51 percent) were equipped with A/C, and a total of 11,997 (10.17 percent) of the 117,964 mid-years built between 1963 and 1967 were sold with the factory refrigerated air setup.

The optional system, RPO C60, continued to grow in popularity--over half of all Corvettes produced were equipped with factory air in 1971, and by 1979, the last year that "air" was optional, the percentage of air cars was over 87 percent.

If every mid-year in existence was an NCRS Top Flight or Bloomington Gold certified restoration, then there'd be no point in a custom aftermarket air conditioning system for these cars. You'd either have an "air" car, make a "non-air" into an "air" car, or do without. And while it sometimes seems that there are more Top Flight and "Gold" restored '67 big-blocks than Chevrolet originally made, the reality is that there are still thousands of mid-years that are not--and probably never will be--"restos." Many of these '63-67 vintage Vettes are drivers, cruisers, and beloved toys that get taken out for weekend trips. These are the cars that may have long ago had the original numbers-matching engine replaced, they get modern stereos fitted ("custom-fit" units--no butcher jobs, thank you!), power steering and brakes added, and modern radial tires in lieu of bias-ply replacements. These are the sorts of cars to which an owner will add a custom air conditioning system--as long as it's engineered to fit without hacking up the car. After all, there's nothing wrong with enjoying some modern amenities in a classic Corvette.

A modern amenity--air conditioning--that'll bolt into a mid-year and requires no more modifications or "butchery" than a few screw-sized holes to be drilled sounds like an excellent idea to us. That was our thinking when we heard about Classic Auto Air's "Perfect Fit" series A/C setup for '63-67 Vettes that we were told also included new heater and defrost systems. So when they (Classic Auto Air) offered to send us a system to evaluate, we took them up on the offer. And that, of course, meant we had to find a suitable mid-year to be used as a Team VETTE testbed.

The suitable car happened to be Mary and Rick McKenrick's '64 convertible, a car that's been the subject of a couple prior tech articles, including a retro-fit power steering installation back in the August 2000 issue. It's a close-to-stock, but non-numbers-matching, weekend toy and cruiser--an excellent recipient for a non-stock but no-butchering-required air conditioning system. Before we went any further, we asked Mary if we could borrow her car for a few days--and give it back with air conditioning. No surprise, her answer was along the lines of, "Of course! When do you need it?"

The next step (something that's not quite as critical if your car has an original engine with original-style accessories--more on this later), was to determine exactly what we were working with, i.e. radiator core support opening (there are at least 11 different core supports for '63-67 Corvettes, and at least two different opening widths), what accessories were on the engine, where they were located, and something we hadn't given any thought to--"short" or "long" water pump.

Okay, the car's a '64 and it was first sold with a 250hp 327 and Powerglide, both of which were replaced many years ago with a '72-or-so vintage passenger car 350 and TH350 automatic. Accessories? An alternator and the recently added power steering pump; alternator high on the passenger side, power steering pump low on the driver's side. And it had the "long" water pump.

We placed an order with Classic Auto Air, then approached Bill Kenney of Kenney's Street Rod Garage about doing the installation. Why a street rod shop? The Corvette we're dealing with, while stock appearing to the average onlooker, is more definitely NOT in "as-built" configuration, and we are not doing a restoration-type article using New Old Stock, reproduction, or remanufactured original parts; we're using specialty parts to modify the car, albeit for improvements in comfort rather than in speed or handling. In other words, a particular job that could be viewed as "one off," one that might entail some creative and well-crafted solutions to unexpected complications--the sorts of things that someone who builds and services special-built cars deals with on a daily basis.

Photos are the most effective way to show the nuts and bolts of the installation, and the sidebar goes into some hopefully correct and helpful detail about the "short" and "long" water pump situation. So at this point we're going to offer up some comments and observations, both Bill Kenney's and our own.

The system is very well crafted and the components appear to be of consistently top quality. An experienced home mechanic, well equipped with tools, jacks and stands, and a couple free weekends (we're allowing for beer breaks and the obligatory when friends drop in to see how the job's coming along) should be able to handle every aspect of the installation except for charging the system once the installation is complete. A qualified shop (a specialty shop like we used or almost any Corvette specialist) should be able to do the job in somewhere between a minimum of 8 to 20 man-hours depending on the particular car.

If you do it yourself, you will need new heater hoses; pick up about 4 feet of each diameter hose. One of the first things you'll do is drain the cooling system; unless your car has fresh coolant (an antifreeze and water mix), get a gallon or two of a good quality antifreeze at the same time you're buying the heater hoses. An accessory drive belt for the new A/C compressor and the relocated alternator are NOT included (too many production variables, although a 60-61-inch belt is suggested) so make sure you have some heavy twine or something similar to use for getting close-to-right length belts from the local auto parts store. Some wire harness splicing is necessary, and relocating the alternator means that its leads will need to be lengthened 2-3 feet (to reach from the passenger side all the way across the engine to the driver's side), so you'll need wire cutting and splicing tools, an assortment of connectors, and appropriate gauge wire (check before you start the job) for lengthening the alternators leads.

Whether you tackle this job yourself (and while it can be quite time consuming, it is very do-able by any reasonably skilled enthusiast with a good selection of tools and basic garage equipment) or choose to have the entire job handled by a pro, we have a final suggestion: The installer will have to remove knobs, then extract and drill out two of the four dash bezels above the radio (FAN TEMP PULL and AIR PULL OFF). Unless the car has had a thorough interior restoration, those old plastic bezels are nearly 40 years old and are brittle--we guaranty it. Ahead of time, order a new set of bezels, knobs, and knob spacers) from any of the reputable Corvette parts suppliers that advertise in VETTE. New repops will look better than the old stuff, they're not expensive, and it's very probable that one or more of the original pieces is going to break either while being removed or when the center opening is being enlarged.

We ran into some unexpected problems thanks to having a later, long-pump engine in an early (i.e. '63-64) chassis with the no-recess front crossmember. It took some creative jury-rigging by Bill Kenney to overcome the problem (see sidebar). The instructions were comprehensive, yet in a few instances contradictory or seemed to jump around. This was a very early production system; we discussed the instructions with the crew at A.C.C. and have been assured that these minor quibbles will be corrected. But, overall this is a very well done system and the components seem to be quite well engineered. Kenney was very favorably impressed with it, which reflects well on the system, coming from an experienced and talented street rod andcustom car fabricator.

Best of all, once the installation was completed, we took the '64 to Mary McKenrick's brother-in-law Loy's shop (Auto Perfections), where Loy threw a charge of environmentally friendly 134a refrigerant into the system. With the system fully charged and ON, we stuck a thermometer in several of the vents and got readings in the low 40-degree range--more than cold enough to throw big chill into a mid-year's cockpit on the hottest summer day. Cool!

If there was one thing on this installation that made us nuts (or at least nuttier than we already are) it was the "short pump, long pump" question. It was easy enough to take a quick measurement and determine that Mary McKenrick's '72 small-block-powered '64 Corvette had a long pump. It's kind of hard to NOT tell the difference, as the short pump has legs that are over an inch shorter than on a long pump.

We measured Mary's car, took pictures from all topside angles under the hood, sent the info and photos off to Classic Auto Air, and talked over the details with C.A.A.'s very-knowledgeable president, Al Sedita. When the A/C system arrived, we opened it up, looked over everything, and were favorably impressed with the quality. As mentioned in the text, the car's alternator was mounted on the passenger side of the engine--right where the compressor needs to go. So as part of the system, C.A.A. included exceptionally well-crafted new steel mounting brackets for relocating the alternator to the driver's side and for mounting the compressor on the passenger side, and both sets of custom brackets were specifically for long pump applications. They also included new OEM two-groove water pump and three-groove crank pulleys.

This is extremely elementary, but as a "just in case" we'll bring it up now. All pulleys and drive belts for accessories must line up with one another. If you have an engine with a long water pump, the water pump pulley and the groove(s) for the belt(s) will be correspondingly farther forward than they would be on a short pump, and if the water pump pulley is farther forward, so must the crankshaft pulley's groove(s) and the mounting points for accessories including the alternator and, if applicable, power steering pump and/or air conditioning compressor.

All was well--up to the moment that Jr. went to install the new crank pulley. "We got a problem!" he hollered to Bill and me, and when we peered into the front of the compartment, it was obvious that we had a helluva problem.

Let me backtrack for a moment. For those of you that have immersed yourselves in Chevy V-8s for many years (or are familiar with almost every little detail and running production change on said engines at least into the mid-to-late '70s), the following will likely be old hat. I hope what follows will be informative and of some help to at least a few readers...

During the first two decades of the Chevrolet V-8, a great variety of water pump configurations were utilized. The one constant, at least through the 1968 model year, was the length of the leg, i.e. the distance the body of the pump stood away from the front of the block (this appears to hold true for '65-68 big-blocks as well as for all small-blocks). All the various and sundry water pumps were of a "short leg" design. Starting in 1969, with the sole exception of the Corvette, the pumps were changed to a "long leg" design--Corvettes used the short leg water pump through the end of 1970. The '71-82 (the latest for which we have reference data) Corvettes used a shorter long-leg pump than other small-blocks.

Obviously, this can be of critical importance for pulley and accessory mounting, and for proper alignment of the accessory drive belts. Not so obvious to any of us involved with this particular project was that the length of the water pump makes a world of difference in second and early third generation frames. (A chorus of, "Well, duh" is now in order from all of you who are highly knowledgeable the nuances of mid-year and Shark frames.) For those of you (myself and everyone else involved with this installation included) who are less than experts when it comes to mid-year and Shark frames, read on.

The basic configuration of the Corvette frame remained the same from 1963-82 with many components (including nearly all of the front and rear suspensions) being interchangeable. The differences lie in the details (all sorts of brackets, mounts, and holes, and most noticeably, the ends of the frame) due to the changes required to meet the DOT-mandated 5 mph "safety" bumpers. The transmission crossmembers in mid-years and early Sharks were welded to the frame rails; later Sharks had bolt-in, removable crossmembers. Beginning in 1968, the rear rail-to-main frame area received additional, diagonal braces. And the front crossmember was changed at least once. The 1963 and '64 frames had a fairly square shaped front crossmember; all 1965 and later frames had a rather large recess centered on the rear side and top of the crossmember to allow needed extra room for the crankshaft pulley that would appear in 1965 on the 396-cid big-block. (Richard F. Newton's CORVETTE Restoration Guide 1963-1967 from MBI Publishing has an excellent chapter about Sting Ray frames.)

Our subject '64 convertible had an original frame with no large crankshaft pulley depression, a '72 engine with a standard long-leg water pump and appropriately mounted accessories, and no room for the multi-groove crank pulley that Classic Auto Air supplied with their kit. Kenney ended up retaining the original single-groove crank pulley (NO cutting the crossmember for clearance allowed!), re-aligned the accessories, and managed to set things up so that the three accessories are driven off of a one-groove crank pulley and the original two-groove water pump pulley. The alternatives in this situation were to abandon the A/C installation (not an option), acquire and install a short-leg water pump and all related accessories and bracketry, or to notch and reinforce the front crossmember (again, not an option for this particular car, and not one I'd consider if it was mine).

After what we (Bill Kenney, his son Jr., and yours truly) went through making a passenger car long pump setup work where it wasn't supposed to, we have some recommendations. Please note that this should not reflect at all negatively on Classic Auto Air--they supplied a kit based on exactly the specification that were provided, and none of us were aware at the time that the '72 passenger car engine that had long-ago been installed in Mary McKenrick's '64 would be capable of causing some fairly serious problems.

Without test fitting the same pulleys, brackets, and accessories on a similar spec engine in a '65-67 chassis (with its recessed center front crossmember) we can't say for certain that the arrangement that caused us grief in a '64 would--or wouldn't--fit fine in a later Sting Ray. Personally we wouldn't risk it. If we knew then what we know now, and if Mary's '64 was ours, we would dump the long pump and related parts, andreconfigure it with a short (i.e. '70 or earlier Corvette-specific "short") pump plus the correct accessories, brackets, etc. It would cause a lot fewer hassles in the long run. And we hope that what we've learned the hard way may help a few of you avoid experiencing the hassles that we did.

Editor's note: We've made every effort to ensure that the information we've presented above is accurate. In addition to Richard F. Newton's book, we also referred to Alan L. Colvin's superb CHEVROLET By The Numbers series and his new book CORVETTE By The Numbers 1955-82, plus drawings and other data from the Weiand division of Holley Performance Products. Mr. Colvin's books are available from Bentley Publishers.


Here 'tis, Classic Auto Air's "Perfect Fit" air conditioning system for mid-years, laid out on a bench at Kenney's Street Rod Garage and ready to be installed.

Look at the blankets and fender covers draped over the nose and both fenders of this '64. This is a sign of a shop that is careful with the cars they work on.

Before starting the installation, Bill and Jr. disconnected the battery, then carefully removed the hood. While Bill removed the glovebox liner, frame, and door as an assembly, Jr. unbolted the alternator.

After draining the radiator and engine of coolant, then removing the old heater hoses, Jr. and Bill disconnected the vent and heater control cables, unplugged the heater blower motor and fan, and removed the entire inner and outer (engine compartment side) heater box assembly...

This is one of the two block-off panels that replace the outer heater cover.

Next was to test-fit the "Power Pack" (the new and very compact, in/under dash heater and air conditioning unit) within the limited space in the mid-year's dash.

Then, with the Power Pack on a work bench, Bill began cutting the new flex hose (ducting) to the designated lengths and attached each segment to its specified outlet on the Power Pack case. By the time he got done, it looked like a bizarre automotive Medusa from Greek mythology.

While Bill was occupied with the Power Pack, Jr. removed the factory defroster ducting from beneath the center of the dash, then dismantled the original heater and vent control cables and knobs. Both trim bezels and the two holes in the dash need to be reamed out to 7/16-inch diameter. The old bezels are likely to be brittle and are very prone to breaking--this is where and why we recommend ordering new bezels and having them on hand before beginning the installation.

Satisfied that he has the two pieces lined up and fitting correctly, Chad marks several key lines on the parts to ensure he has them lined up right when the welding starts.

Once the plate and Power Pack are united, the plate (with the new heater ducts and the A/C fittings protruding through the pre-formed openings) is attached to the firewall. Now the Power Pack is attached to the cowl crossbrace with the supplied self-tapping metal screws.

Both original vent and heater control knobs will need the holes in the back opened up to 1/4-inch diameter, and the cable control knob will also have to be drilled and tapped (threaded) on the shaft for a new set screw. After the Power Pack has been positioned and the new control cables are in place, the knobs can be affixed.

Jr., being a lot younger and more nimble, gets the task of running the ducts into position, hooking them up with the new vents, and installing them under the dash, and on both side of the console.

While Jr. got to do his best imitation of a contortionist, Bill busied himself in the engine compartment, installing the new A/C compressor...

...followed by the relocation brackets to position the alternator on the driver's side of the engine, and the alternator itself.

It's new heater hose time. This is a no-brainer except for one minor detail--locating the heater's water valve. It's operated from inside the car by the temperature control cable, and if it, the valve, is not located correctly, it will not operate correctly. There was no specified position in the instructions (something we've pointed out and were told would be rectified), so Bill had to spend a few extra minutes getting the valve satisfactorily positioned.

Jr. begins connecting the A/C lines to the compressor, and Power Pack, and routes 'em forward and over the core support to where the condenser and dryer will be located.

We discussed the long vs. short water pump situation in the sidebar, so suffice it to say that once Bill Kenney got that problem resolved and, after using a length of twine to simulate the length of drive belts needed, and appropriate belts delivered, it was time to install 'em and tighten up the accessories with the correct tension on the belts. Jr. tugs while Bill tightens.

The system comes with almost everything you'd need for the installation. One of the few other "oops" situations we ran into was the wiring harness for the relocated alternator--or more correctly, lack thereof. Kenney's next door neighbor is a shop called Car-Go Alternator & Starter Supply Inc. (1-800-491-4490). About five minutes after getting a semi panicky call, the owner of Car-Go walked into Kenney's shop with a loom he'd whipped together, complete with correct Chevy connectors. (Thanks!). Bill is seen here running the new loom from the alternator to the '64 Corvette's original wiring harness.

The finished installation looks almost OE (original equipment) under the hood. The real giveaways are the modern, highly efficient and lightweight compressor, the neat custom brackets (as opposed to the humongous and hefty factory pieces), and the auxiliary electric fans up front, ahead of the radiator and condenser.

Because the entire heating and air conditioning system's "Power Pack" is mounted inside the car, behind the dash (with just a pair of flat block-off plates on the firewall), the depth of the glovebox is reduced by about half. Classic Auto Air includes a new, molded plastic liner with the system. After attaching the new liner to the glovebox frame and door, Bill installs it in Mary McKenrick's '64 convertible.

Here's a look at the A/C vents as installed. Personally, we'd like to see some sort of cover (slotted, louvered, or whatever) over the blower fan's exposed "squirrel cage."

The final step was to get the system charged. In this instance, at Mary's brother-in-law Loy's shop, Auto Perfections.

Only one thing really matters, once the installation is completed--does it work? Well, the thermometer is reading an air temperature of about 42 degrees at the vent on the passenger side of the console, so, yeah, it works. Big time!


Classic Auto Air
Tampa, FL 33634
La Habra,, CA 90631

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