The origins of the Camaro can be traced to the first week of April 1964, when vehicle number 64163 was tested at the General Motors Proving Grounds. It was a 1964 1/2 Mustang hardtop with a six-cylinder engine and three-speed manual transmission. A copy of the 2,000-mile break-in test report, dated April 6, 1964, indicates GM had already procured and was testing a new Mustang 11 days prior to the public introduction of Ford's ponycar. According to Alex Mair, who joined the Camaro platform in 1966 as chief passenger car engineer, GM and Ford then had a reciprocal understanding to share new products for analysis prior to their introduction. "We always had Ford products 2 to 4 weeks ahead of the formal announcement," said Alex. It was a shake-hands agreement that the public didn't know about." And so GM was able to test the new Mustang before Ford ever released it to the public.
Although it would take four months before GM management gave the go-ahead to start on the F-car (F was the corporation's designation for the new body), Chevrolet Engineering was already at work targeting the Mustang's basic specifications and dimensions for their own ponycar. Stylists used the 1964 Super Nova show car as a starting point for the F-car, and called it Project XP-836.
When work began in August of 1964 on the F-car, the following set of specific baselines was established by Chevrolet for the final design:* Distinctively modern aerodynamic styling for a clean, functional appearance* Small, highly maneuverable size with packaging for four passengers* A very broad range of available performance capability* Quick, sharply-defined roadability with a firm, yet comfortable ride* "Cockpit-type" interiors for close driver identification* An evolutionary, rather than revolutionary, basic design approach to maintain maximum value for the customer* Wide selection of mechanical and aesthetic equipment to allow custom tailoring for needs and desires
Chevrolet engineering also broke down the design and construction of the Camaro into four major construction groups:* Bolted-on, front end sheetmetal* Unitized body construction with the rear framing elements incorporated into the underbody* Driveline: solid rear axle and single-leaf rear suspension combined into a simple and efficient Hotchkiss drive system* A front chassis unit consisting of the engine, transmission, front suspension, front brakes, steering gear, and linkage mounted on a separate, extended-rail partial front frame
Chassis Engineer, Paul King, recalled mounting pressure as the original perimeters of the F-car were laid out: "I was in the development group at the time. We were getting a lot of stuff pumped into the car from other directions than usual. Road noise and road impact were harder to isolate. If there was an assembly consideration, we had the manufacturing people on our side. They were concerned about line spacing on the assembly line, so the overall length of the vehicle was important. We were pressured to get a car like the Mustang out both in image and in price. That forced us to want to do the car in a big hurry."
Chassis Design And The Art Of CompromiseTo reduce engineering costs, part of the F-car's structural design was borrowed from the 1968 Chevy II. Since its introduction in 1962, the Chevy II has utilized unit body construction, to which all chassis components are attached to underbody framing elements. While this was an inexpensive way to build a low-price car, it left much to be desired, resulting in creaks, rattles, and a harsh ride. Using a full-frame beneath the F-car would have been too costly, though, so GM engineers combined aspects of several European designs, adapting an extended-rail front subframe to attach to a unit body via four rubber body bushings. With two rubber body bushings at the cowl dash legs, and two in the area under the front seats at end of the subframe, vibrations, road noise, and engine noise were successfully isolated from the passenger compartment. And with the transmission attached to a crossmember at the rear of the subframe, and two mounts at the front for sheet metal attachment, the subframe was similar to composite body/full-frame Chevrolet cars like the Chevelle.
Using the 1965 Corvair as a target, Chevrolet engineers modeled the F-car lower in height, with a pronounced long-hood, short-deck look, while still incorporating the Corvair's "coke-bottle" kick-up from the leading edge of the rear quarters. By assigning the F-car a wheelbase of 108 inches, the front overhang measured in at 36.6 inches, leaving a relatively short rear deck. This proportioning allowed the instrument panel, cowl, and front seats to be positioned closer to the rear, more comparable to the Corvette than the Chevy II. Stylists would still struggle with the high cowl inherited by this shared design, though, and several alternative approaches to cowl height and hood length would be attempted.
By combining a subframe attached to a unit body, Chevrolet engineering was able to create meaningful cost savings. The subframe was developed to accept the standard GM design SLA front suspension with unequal upper and lower A-arms, monotube shocks, and coil springs with front stabilizer bar. The 1968 Chevy II would also significantly benefit from the F-car's developments, including the subframe, front suspension design, braking systems, and powertrains. By spreading the cost of these components across model lines, Chevrolet could keep the price per unit down, thus making the products both competitive for the consumer and profitable for the company.
As a clean sheet project, Chevrolet Engineering applied the newest available technology to determine the characteristics of the suspension. Although primitive by today's standards, analog computer simulation techniques were used for the first time to analyze the perimeters Chevrolet engineers had designed for the F-car. The computer-simulated engineering, provided by the Engineering Mechanics Department of General Motors Research Laboratories, was essential in setting the spring deflection rates, anti-roll bar rates, shock valving, and other ride and handling characteristics.
At the time, using computers to evaluate and analyze suspension settings was a new science, and not everyone in Chevorlet Engineering was sold on the idea. "We were willing to gamble a little bit on some of our design decisions by what the computer told us," said Paul. "That was a new tool for us, and we weren't sure how much confidence to put in it. You were creating a design and then making some decisions based on the computer saying 'if you do this, it will be that.' We didn't know how much credence to give to these sorts of indications. So for a while the computer analysis followed the actual design until we grew more confident of its analysis."
The rear suspension consisted of a Hotchkiss-type arrangement mounted on mono-leaf, semi-elliptical springs with direct, double-acting hydraulic shock absorbers, and installed directly to reinforced points at the rear body shell. Because of the shorter length available at the rear, the chrome-carbon, steel leaf springs were 6.5 inches shorter than the Chevy II's 62.5-inch springs, as well as 2.5 pounds lighter. To deliver excellent handling characteristics and still provide adequate body isolation, a computer program was devised to analyze suspension reaction to changes in bushing durometer. The tests revealed that a single, low-durometer bushing was ideal for the front spring bushing, and at the rear, two-piece bushings from lower durometer rubber. This combination provided the much sought-after compromise between rear suspension control and body isolation from drivetrain and road noise.
Computer analyses also indicated the advantages to mounting the rear shock absorbers outboard of the springs, in an almost-vertical arrangement-a divergance from the standard diagonal configuration. Chevrolet engineers determined this would improve tire adhesion on washboard road surfaces as well as cornering. Paul remembers that only later did they discover that springs wind under severe braking or severe launch, and worsen with the big-block cars, which generate tremendous torque on the rear suspension assembly. Several methods to eliminate the problem were explored, including frame ties which would have connected the trailing edge of the front subframe to the leading edge of the rear spring. Cost considerations eliminated that possibility, and the basic design format was retained until the end of the 1967 model year; however, a traction bar was added to the right monospring, alleviating some of the wheelhop problems.
Preproduction mules (disguised in Chevy II sheet metal), as well as a group of competitor cars, were driven across the United States from New England to California, and to GM's Desert Proving Grounds near Phoenix, in September 1964. Several were also taken to GM's Milford, Michigan Proving Grounds, and shown the difference between the computer simulations, which were constrained by the design perimeters, and real-world test conditions. The first pretest vehicle provided directional control response baseline measurements, which were then compared to the computer data. The results indicated that the real-world characteristics of the suspension design were in line with the low lateral acceleration computer simulations; the opposite was true at high lateral acceleration, with the mule having more understeer. Roll rates and angles were 10 percent lower, indicating the suspension did not share the simulation's characteristics.
Styling ChallengesWhen the engineering specifications for the new F-car arrived on designer Henry Haga's desk, in Chevrolet's Studio II on August 26, it was obvious that there was a lot of Chevy II architecture in the numbers. These numbers required the height of the cowl and the distance from the center of the front axle to the dash to be the same for the Chevy II and the F-car. For the bread-and-butter Chevy II, these numbers would translate nicely into a two- or four-door design. For the F-car, however, it resulted in a cowl that was too high in the eye of the designers, and too short between the front wheel and the dash. Designers then worked to achieve a lower cowl by giving the windshield a more severe rake and thinning the A pillars
By December of 1964, the basic shell was complete. The look was fluid-a new approach at GM, which began with the 1965 Corvair and resurfaced on many restyled 1966 GM cars. Angles and beveled lines were softened into flowing curves, with quarter panels ramping upwards (the famous GM "Coke Bottle" look), and a seamless integration of the C-pillar from top to deck. From the front, the body had a fuselage appearance as it rolled down into the rocker panels. The curved side glass area and smooth rear deck strongly contradicted the Mustang's chiseled appearance, and although the dimensions of the two ponycars were virtually identical, the F-car's design was more gentle and streamlined. Chevrolet literature highlighted the curved contours of the F-car's design, and noted that "one interesting styling aspect of these rounded beauty surfaces is the feeling of motion achieved by light reflections while the car is stationary as well as moving." By August 1965, the front grille, headlamp design, and placement had been approved.
In fact, when taken to the wind tunnel-attended by a Chevrolet engineer, a stylist, and a clay modeler in February 1965-the first Camaro quarter-scale models exhibited excellent aerodynamic characteristics. In a series of 76 trials conducted at the Vought Aircraft wind tunnel in Dallas, a variety of different angles and positions were tested to accumulate data on six major forces affecting aerodynamics. Lift, drag, side forces, pitching, yawing, and rolling moments were all recorded and fed into a computer. Airflow visualization tests using the ink stain method were also performed and photographed after each run. The end result of this 11-day examination proved the basic design of the F-car remarkably smooth and in need of little tweaking. Styling cleaned up the leading edges of the front fenders and reduced front valance rake, and additional data was used to adjust the Z/28's chin and rear spoiler.
In retrospect, it was fortunate that the Camaro's body was inherently aerodynamic, as there would not have been adequate time to experiment with radically different designs and still deliver to market by fall of 1966. Paul recalls: "To me, wind tunnel testing was interesting at that time, but we were going to build the car the way it was regardless of what the wind tunnel said. We had a job to do and we were going to do it. If the wind tunnel results were positive, that was nice. If they were bad, that was too bad, because we were going to build the car anyway."