Chevrolet Corvair

The Chevrolet Corvair is an automobile that was produced by the Chevrolet division of General Motors for the 1960–1969 model years. The Corvair features a rear-mounted, air-cooled, horizontally-opposed six-cylinder aluminum engine. The first Corvair engine produced 80 hp (60 kW), but later versions developed as much as 180 hp (134 kW). It was offered in a wide range of body styles, including two-door coupes and convertibles, four-door sedans, and four-door station wagons. The Corvair — like the Ford Falcon and the Plymouth Valiant— was one of the first entries of a new compact car class. These were offered in response to the small, fuel-efficient automobiles being imported from Europe by Volkswagen, Renault and others. Initially marketed as a family economy sedan, with the mid-1960 introduction of the Monza Coupe, the Corvair found a new sporty-car niche, and influenced Ford to introduce the Mustang in 1964. The Corvair Monza Spyder and later Corsa models were one of the first American cars to offer a turbocharged engine. The nameplate was also offered as a passenger compact van called the Greenbrier, and commercial vehicles were also initially offered; the "Corvan 95" panel van and two versions of a two-door pickup truck. A proposed Pontiac version, the Polaris, was never built; the more-conventional Tempest was selected, instead.

History
The Corvair name originated as a fastback show car in 1954, which, like many Chevrolet concept cars of the period, including the Chevrolet Nomad and Chevrolet Impala, was based on the Corvette. The design was championed by Ed Cole, Chevrolet's chief engineer in the early 1950s and general manager in the late 1950s, as an answer to the growing popularity of small, lightweight imported cars.

Design began in 1956 under the auspices of Ed Cole, and the first vehicles rolled off the assembly line in late 1959 as part of the 1960 model year (in which it was named Motor Trend magazine's Car of the Year). For 24 hours, two Corvairs were tested at the Riverside International Raceway in Riverside, California. One car rolled over, but the other completed the drive, only losing a quart (1 L) of oil (Source: Riverside Raceway Palace of Speed by Dick Wallen).

The Corvair enjoyed a ten model year run, and was finally discontinued in May 1969 due to plummeting sales. A variety of factors contributed to the model's 96% drop in sales from 1965 to the last 1969 models. The Corvair faced increasing competition from the Ford Mustang and other 'pony cars' - ironically, a market pioneered by the 1960 Corvair Monza. Safety issues were raised, especially by Ralph Nader's 1965 book Unsafe at Any Speed. The car's design was costly to produce and did not command a premium price on the showroom floor. Engineers experienced difficulties adapting the basic engine design to the tighter emissions standards proposed for 1972. Lastly, a general lack of interest at General Motors, including an almost complete lack of advertising from 1967 onwards (the company's "by-request-only" 1969 Corvair brochure was a mere 4 pages long, and the 500 Sport Coupe wasn't even illustrated) contributed to the model's demise.

The Corvair was a successful model for Chevrolet, with annual unit sales exceeding 200,000 for many years. Chevrolet deliberately designed the Corvair as a radical departure from the conventional Chevrolet. The rear engine offered enormous packaging and economy advantages, providing the car with a lower silhouette, flattening passenger compartment floor, obviating the need for power assists, reducing the need for air conditioning (due to the absence of engine heat blowing over the passenger compartment), and offering dramatic improvements in ride comfort, traction and braking balance. The radically different design also attracted customers from other makes, primarily imports. This was an important, and often under-emphasized, driver for the Corvair's success. Unlike the Falcon and Valiant nameplates, whose conventional designs tended to poach customers from the cheaper but profit-driving full-size models from their respective manufacturers, the Corvair siphoned customers from makes such as Volvo or VW. Because such customers had not been likely to contemplate a larger Chevrolet Biscayne (which cost only slightly more), each Corvair sold did not translate into a Biscayne that was lost. This was in direct contrast to the situation at Ford, where the Falcon nearly ate its maker alive by stealing sales from the basic large Ford sedan. Corvair sales were almost entirely "extra business" for Chevrolet.

The early 1960 models were conceived as economy cars, and had boxy styling, basic trim, and few amenities to keep prices down, despite the relatively expensive and unique power train. A novel feature available for certain higher-level two-door models was a fold-down rear seat. Passenger compartment heat was supplied by a gasoline heater mounted next to the spare tire in the luggage compartment. The line quickly grew from plain, four-door sedans with bench seats (the base 500 and slightly more upscale 700) to the Monza 900, a two-door coupé with bucket seats and plush trim, introduced late in the model year. An available option was a more powerful engine, rated at 95 horsepower thanks to a more radical camshaft and low-restriction exhaust. Despite its late introduction, the Monza sold 12,000 copies, making it one of the most popular Corvairs.

1961
1961 Chevrolet added an optional four-speed manual transmission (late in 1960, few produced prior to 1961 introduction) to augment the standard three-speed manual and optional two-speed Powerglide automatic. The Corvair engine received its first size increase to 145 in³, courtesy of a slight increase in bore size. The base engine was still rated at 80 hp (60 kW) when paired with the manual transmissions and 84 hp (63 kW) when mated to the optional automatic transmission in Monza models. The high-performance engine was rated at 98 hp (73 kW). To increase luggage capacity in the front, the spare tire was relocated to the engine compartment in cars not ordered with All Weather air conditioning, and the gasoline heater was replaced by a system of ducts that redirected warmed air from the cylinder heads to the passenger compartment. The gasoline heater remained available as an option through 1964.

Corvair was the first of the compacts to offer factory air conditioning, as a mid 1961 option introduction. The large condenser lay flat atop the horizontal engine fan. A large, green painted reverse rotation version of the standard GM Frigidaire air conditioning compressor was used, and an evaporator housing was added under the dash with integrated outlets surrounding the radio housing. All Weather Air Conditioning was not available on wagons, Greenbrier/Corvair 95 or the turbocharged models introduced later, due to space conflicts in those body styles.

A station wagon, the Lakewood, was also added to the lineup in 1961, and it contained a total of 68 ft³ (1.9 m³) of cargo room — 58 in the main passenger compartment, and another 10 in the "trunk" under the hood.

That same year, Chevrolet also introduced the Corvair 95 line of light-duty truck, which used the Corvair driveline and were forward-control, with the driver sitting over the front wheels, as in the Volkswagen Type 2. The Corvan model was available in a myriad of configurations as both a panel van and a window van. There were also two models of pickup available. The Loadside was a fairly typical pickup of the era, except for the rear engine, forward controls, and a strange pit in the middle of the bed, The more popular pickup was the Rampside model, which, as its name implies, had a large fold-down ramp on the side of the pickup bed. Rampsides were used by the Bell System because of the ease with which cable reels could be rolled in and out of the bed. Fleet sales of Corvair commercial vehicles were poor due to an approximately $100 premium over competitive Ford products: If you bought 25 trucks, you essentially got one extra Ford for free. This disadvantage would seriously impact Corvair 95 sales, and ultimately cause the line to be discontinued in favor of a profoundly basic Chevy II based panel truck in 1964.

The Greenbrier Sportswagon used the same body as the Corvan with window option, but was marketed as a station wagon like the Lakewood, and was available with trim and paint options similar to the cars, arguably making it the first American minivan.

Continuing from the end of the previous year was the Monza, heavily promoted and sometimes considered "the poor man's Porsche." The Monza was expanded to a four-door as well as a two-door coupe, and garnered around 144,000 sales.

1962 – 1963
In 1962, Chevrolet introduced the 150 hp (112 kW) turbocharged Monza Spyder option for Monza coupes and convertibles mid year, making the Corvair one of the first two production automobiles to come with a turbocharger as a factory option, with the Oldsmobile F-85 Turbo Jetfire of the same year. The 500 station wagon was dropped in favor of the Monza wagon at introduction, however all station wagons were discontinued mid year to create more capacity for new models like the convertible and Chevy II. Metallic brake linings and a heavy duty suspension consisting of a front anti roll bar, rear axle limit straps, revised spring rates and recalibrated shock absorbers were introduced as optional equipment and recommended for Spyders. Monza Spyder featured a multi-gauge instrument cluster which included a tachometer, cylinder head temperature gauge and intake manifold pressure gauge in addition to the turbocharged high performance engine.

The 1963 model year saw the end of the Loadside pickup, and the availability of a long 3.08 gear for improved fuel economy, but the Corvair otherwise remained largely carryover with minor trim and engineering changes (self adjusting brakes) from 1962.

1964
Significant engineering and safety changes occurred in 1964, while the bodies and models available remained the same.

The lineup remained relatively unchanged for the 1964 model year, with the exception of the engine growing from 145 to 164 in³ (2.3 to 2.7 L) due to an increase in stroke; the base power growing from 80 to 95 hp (60 to 70 kW), and the high performance engine growing from 95 to 110 hp (70 to 80 kW). The Spyder engine remained rated at 150 hp (112 kW) despite the displacement increase of the engine. The Rampside pickup was discontinued at the end of the model year.

1964 also saw a critical improvement in the Corvair's suspension; the car's swing axle rear suspension was tamed by use of an additional transverse leaf spring carrying a high proportion of the rear weight, in an effort to diminish rear roll stiffness and foster more neutral handling attributes. Spring rates were much softer at both ends of the car in 1964 compared to previous models, and the heavy duty suspension was no longer optional, although all models now had an (even larger) front anti roll bar standard. Brakes were mildly improved by finned rear drums.

However, a young lawyer named Ralph Nader had written a book called Unsafe at Any Speed in which the 1960-63 Corvair (accused by Nader of a greater tendency to cause loss of driver control, spin out or even roll over in many situations) was used as a dramatic case study. The Nader book, which was published in 1965, came as a blow to sales of the Corvair line. The sporty, inexpensive Ford Mustang, based on the conventionally designed Ford Falcon and introduced in April 1964 in response to the market pioneered by the Corvair Monza also impacted heavily on Corvair sales, even after the sensational 1965 redesign.

1965
A dramatic redesign of the Corvair body and suspension and two powerful new engines came in 1965. The new body style showed influence from Chevrolet Corvette Stingray and the 1963 Buick Riviera, with 'coke bottle styling' that set the trend for GM cars for the next fifteen years- foreshadowing the 1967 Chevrolet Camaro that eventually replaced the Corvair. Many consider the second generation to still look contemporary in contrast to the first generation body. A new fully independent suspension similar to that used on the Corvette replaced the original swing axle rear suspension. Car and Driver magazine's David E. Davis Jr. showed wild enthusiasm for the 1965 Corvair in their October 1964 issue. For the first time, none of the passenger cars had a "B" pillar, making all closed models true hardtops.

"And it is here too, that we have to go on record and say that the Corvair is - in our opinion - the most important new car of the entire crop of '65 models, and the most beautiful car to appear in this country since before World War II."

"When the pictures of the '65 Corvair arrived in our offices, the man who opened the envelope actually let out a great shout of delight and amazement on first seeing the car, and in thirty seconds the whole staff was charging around, each wanting to be the first to show somebody else, each wanting the vicarious kick of hearing that characteristic war-whoop from the first-time viewer."

"Our ardor had cooled a little by the time we got to drive the cars - then we went nuts all over again. The new rear suspension, the new softer spring rates in front, the bigger brakes, the addition of some more horsepower, all these factors had us driving around like idiots - zooming around the handling loop dragging with each other, standing on the brakes - until we had to reluctantly turn the car over to some other impatient journalist. We were actually annoyed about having to drive the new Sting Ray and the new Impala SS with a great, storming 409 to propel it"

"The '65 Corvair is an outstanding car. It doesn't go fast enough, but we love it."

Many new options and refinements appeared in the beautiful (according to critics such as Car and Driver) new 1965 redesign. Fully integrated in-dash All Weather Air Conditioning, a much better heater system, larger brakes borrowed from the Chevelle, a stronger differential ring gear, a Delcotron alternator and significant carburetor and small chassis refinements all occurred. AM/FM radio, FM stereo, telescopically adjustable steering column, and a Special Purpose Chassis Equipment ("Z17") handling package, consisting of a special performance suspension and quick ratio steering box, were significant new options that became available for 1965.

The previous 150 hp (112 kW) Monza Spyder was replaced by the normally-aspirated 140 hp (104 kW) Corsa and the 180 hp (134 kW) Turbocharged engine. The Corsa came standard with an instrument panel featuring a 140 mph speedometer with resettable trip odometer, a 6,000 rpm tachometer, cylinder head temperature gauge, analog clock with a sweeping second hand, a manifold vacuum/pressure gauge and fuel gauge. Also standard was a short throw shifter for the manual transmission (no automatic was offered). The standard equipment Corsa 140 hp (104 kW) engine was notable for the fact that the engine used 4 single-throat carburetors, larger valves, and dual exhaust — the factory's response to a modification hot-rodders had been making since the car first appeared; it was available as an option on other Corvair trim levels. The base 95 hp (71 kW) and 110 hp (82 kW) high performance engines were carried forward from 1964 for the 500 and Monza models.

By this point, the more utilitarian station wagon, panel van, and pickup body styles had all been dropped in favor of the sportier coupe, hardtop sedan and convertible styles. 1965 would be the last year for the Greenbrier window van, which was retained only because of a few fleet orders, with 1528 being built. Chevrolet replaced the Corvair-based vans with the Chevrolet Sportvan/GMC Handi-Van, which used a traditional front engine/rear drive axle borrowed from the Chevy II.

1966 – 1969
The 1966 lineup remained essentially unchanged from 1965, and sales began to decline as a result of Nader's book, the very popular new Mustang that offered V8s up to 271 hp compared to Corvair's 180 hp top powertrain, and rumors of the upcoming "Panther'- the code name for the forthcoming 1967 Camaro slated as the replacement for the Corvair in the sporty car market. The sales decline was also accelerated by a decision at GM to discontinue further development of the Corvair. One change of note was a more robust 4 speed synchromesh transmission for 1966, using the standard Saginaw gear set with 3.11:1 first gear ratio used by other GM 6 cylinder vehicles. The new 3 and 4 speed transmission was capable of handling more stress, though generally much more truck-like in operation than the prior 4 speed transmission which was modeled more along the lines of a Warner, but also a Saginaw product. It was a great improvement over the older 3 speed transmission, having a synchronized first gear. Also, the gear ratios were carried over from other GM cars, and were not optimal for a street-driven Corvair. A small flexible plastic air dam ("spoiler") was installed below the front apron to conceal the front suspension and underbody, and lessen crosswind sensitivity to virtually nil. It is a popular retrofit to the 1965 models both for functional and aesthetic reasons.

In 1967 the Camaro was introduced and the Corvair line was trimmed to the base 500 sedan and coupe, and the Monza sedan, coupe and convertible. The 140 hp (104 kW) and 180 hp (134 kW) engine options were deleted as well, although the 140 hp option would be later reintroduced as a regular production option and would remain available until Corvair production ended. This model year was the first equipped (along with all other domestic GM lines) with true collapsible steering columns, a final response to one of the most valid safety criticisms. GM introduced a 50,000 mile engine warranty on all 1967 models, including the Corvair. Dual circuit master cylinder with warning light, nylon reinforced brake hoses, stronger steel (instead of aluminum) door hinges and soft contoured instrument panel knobs and a vinyl edged day/night mirror were all made standard equipment as well.

In 1968 the line was trimmed even further by discontinuing the four door hardtop models, leaving just three models; 500 Sport Coupe, and Monza Sport Coupe and Convertible. Sales were down to 15,400. All Weather air conditioning was dropped as an option, due to concerns about thermal loading added by the now-standard air injection reactor ("smog pump") which probably hurt sales as factory air became more popular generally in automobiles.

Corvair production finally ceased in 1969 with sales of only 6,000 cars, less than one to each Chevrolet dealership, a victim of Nader's book, Ford's Mustang, and Chevrolet's own Camaro and Nova. Although negative publicity hurt the Corvair, ongoing litigation is believed to have extended the production life of the vehicle, as ending production would have been construed as an admission by General Motors that the product was flawed.

According to researchers such as noted GM historian Dave Newell, GM had already planned on ceasing Corvair production after the 1966 model year to make way for the Camaro. But the timing of Nader's book turned out to be an inconvenience. Not wanting to appear as though they were buckling to Nader's pressure, GM kept the Corvair in production for another three years. The only developmental changes made were to keep in line with government safety and emissions requirements. Another indication of the Corvair's imminent demise was when the 1969 models were introduced: GM equipped its 1969 models one year ahead of Government requirements, with a steering column-mounted, anti-theft ignition switch, and a new, square-shaped ignition key. Nineteen sixty-nine Corvairs got the new key but were the only GM cars to retain the ignition switch on the dashboard, no doubt due to the lack of interest by GM engineering to adapt the Corvair steering column accordingly. How those last 1969 Corvairs were assembled (and the press event held by Chevrolet when car number 6000 rolled off the assembly line) is an interesting part of the Corvair story.

Nineteen sixty-nine Corvairs and Novas were being assembled at the same facility in the Chevrolet/Fisher plant in Willow Run, Michigan. However, demand for Novas was high and almost nonexistent for Corvairs, so a decision was made in November, 1968, to move Corvair assembly to a special area in the plant, dubbed the "Corvair Room," making Corvairs built between that time and May 14, 1969 essentially hand-built (once the bodies were delivered from Fisher Body). A number of well-known Chevy collectors and GM executives expressed interest in purchasing the last Corvair, number 6000, but GM management decided that the Olympic Gold Monza hardtop would not be sold. Most accounts relate that GM scrapped it shortly after it was built. Representatives from the press, along with corporate bigwigs, were present at the small ceremony when car number 6000 got its final fittings and drove off the line to where railroad cars full of new '69 Novas were ready to be shipped to dealers. Reaction to the death of this sporty car was mixed, and extended to both ends of the spectrum, from sadness and regret that such a fine car couldn't make it in the marketplace, to sharp criticism of Chevrolet's decision to continue building the car at all.

General Motors did have plans for a 1970-on model Corvair, essentially a re-skin of the 1965-69 body with new exterior sheetmetal. The car likely would have debuted as a "1970 1/2" model, much as Corvette and Camaro did for 1970. The overall appearance of this third generation Corvair was very similar to the 1973 GM A Body intermediates-- particularly the 1973 Pontiac Grand Am. It retained Corvair proportions, with a rounded sweeping body, terminating in a tapered tail with a glassy roof, featuring fixed quarter windows. This program progressed past the point of full scale clay models before being dropped in early 1968. One interesting project at GM was the Turbo Hydramatic 350 transmission, introduced in the 1968 Camaro and later adopted by most Chevrolet models. It was laid out in a manner that would permit its use in the Corvair, unlike the Turbo Hydramatic 400 and most other designs. Had the 1970-on Corvair been built, it is clear this transmission would have been adapted for the Corvair. The last word on the 1970+ "third generation" Corvair was, "Mr. Cole (GM President Ed Cole, ex-Chevrolet General Manager during Corvair development) is not enthused about this program..."

In what may be the automotive industry’s greatest irony, NHTSA, the federal agency created from Nader’s “consumer advocacy,” investigated the Corvair and issued a report in 1971 clearing the car’s design. But that was two years after the car went out of production, and not nearly as headline-worthy as Nader’s initial claims.

Part of Nader’s evidence against the Corvair was a promotional film created by Ford Motor Company, in which a Ford test driver purposely turned the Corvair in a way to make it spin around. Such films were not uncommon. GM also had films showing the Ford Econoline pickups standing on their noses under heavy braking.

Engineering
The Chevrolet Corvair engine, unique for a United States car, presented a different set of requirements for mechanics, many of whom treated the engine in the same way as they would an engine of normal design, leading to problems.

An engineering weakness not generally highlighted related to fumes and gases entering the passenger area via the heater system, a problem endemic to an air-cooled engine that uses heat radiated from the engine directly to heat air for the passenger compartment. Carbon monoxide and other noxious or deadly gases could enter the passenger areas if exhaust system gaskets aged or failed using this system, since the gaskets were inside the heater box air intakes and air for engine cooling was used for passenger–compartment heating when the heater was on (or leaking). The 1960 model Corvairs used a GM Harrison division gasoline heater located in the front trunk area as its standard heater, similar to the Eberspächer heater offered as an auxiliary heater by Volkswagen as a dealer-installed option. This feature became optional in 1961 and was dropped in 1965 due to weak consumer demand.

Chronic oil leakage from the pushrod tubes, caused by GM's poor choice of pushrod tube seal material, also contaminated the passenger heating air. That air might also become noxious if a 6-inch (152 mm) wide rubber seal almost 16 feet (5 m) long, located between the engine assembly and the body, was not maintained in like-new condition. Another common problem in the earlier years was oil leakage caused by dissimilar metal thermal expansion on the aluminum–and–steel engine. Chevrolet wrestled with several problems of this nature the entire time the Corvair was in production with varying degrees of success.

The interior air would also be contaminated if the voltage regulator allowed an over-voltage condition and the original battery vent hoses were not attached. The battery, which was mounted in the engine compartment, could emit hydrogen if overcharged. Chevrolet installed special battery caps and hoses that vented the battery to air outside the engine compartment, but these were often discarded by owners during the car's life.

The Volkswagen Beetle (Type I), another automobile with an air cooled engine, had a heater system which better isolated fresh air from engine cooling air fumes, and was only susceptible to carbon monoxide contamination from the two heat exchanger to muffler seals at the rear of the engine, as opposed to the eight exhaust joints in the Corvair system. This air contamination problem is illustrated by the fact that many American cities' taxi regulations had prohibited air-cooled engine cars from being used as taxicabs when they derived their heated air from engine exhaust heat, decades before the Corvair and VW Beetle entered the market.

A criticism in Lawyer Ralph Nader's 1965 book concerned the steering column design. Like most cars of its era, the Corvair's steering column was rigid and could impale the driver in a front-end collision. While the Corvair's steering box was mounted ahead of the front cross-member, it was well behind the frame horns, in what would later be called a "crumple zone," and could, in a severe front-end collision, push the steering column and steering wheel toward the driver. In practice, most driver chest injuries were sustained due to the lack of a shoulder belt, rather than steering column intrusion. Any increase in risk of injury due to steering column intrusion in a front-end collision was, however, more than offset by the absence of an incompressible engine and transmission in the front of the vehicle, which commonly intruded into passenger compartments on vehicles of the era. Chevrolet, aware of Nader's criticism, changed the steering shaft to a two-part design with a frangible joint late in the 1965 model year, and a collapsible steering column was provided in 1967, towards the end of the model's life span.

The criticism of the 1960-'63 Corvair handling was not entirely groundless. Although it was a competent handling vehicle as delivered from the factory, with characteristics quite similar to many imported cars, such as Mercedes and Volkswagen, which also used swing axle suspensions with similar handling attributes, there was room for improvement. Advertising in 1960 from domestic competitors showing the results of shooting an arrow weighted at the rear end missing its target widely did little to foster confidence in many minds about the stability of the car.

Chevrolet had tailored the handling of the Corvair by using very wide tires for such a light car (6.50-13, considered wide at the time, even contemporary Corvette used only a 6.70) to bear the weight of the rear and reduced front pressures by about 11 psi to increase front slip angles to balance traction and maintain confident control. If this pressure difference was not maintained, the handling would suffer as in very hard cornering, the rear slip angles would exceed the front slip angles and could lead to spin out or loss of control at very high speeds where the car is traveling dozens of feet per second and small changes in the rate of drift between the opposing ends of the car translated into a departure from the driver's intended course down his lane or in some cases, the road.

Swing axles were a common suspension design during the Corvair era- Millions of Ford pickup trucks were sold well into the 1990's using 'Twin I Beam' which is a swing axle. The advantages of swing axles are quite numerous; very compact packaging, tremendous strength and durability on rough surfaces, very good isolation of road harshness and a very smooth ride due to the camber changes forcing the tire carcass to absorb blows sideways as well as radially on severe bumps.

The primary deficiency of swing axle suspensions is they create a high 'roll center'; the theoretical point the car center of mass pivots around as it leans in cornering. Although a high roll center reduces body roll in cornering, and reduces sensitivity to cambered roads and crosswinds- all good attributes- high roll centers create 'roll stiffness' which is resistance to body roll. This roll stiffness transfers outboard weight shifts in cornering to the outboard tire in a corner. Pre-1965 Corvair has a rear roll center approximately 13" above the road surface and front roll center just slightly below the road surface. This concentration of roll loading on the rear wheels means as the severity of cornering loads increased the weight was transferred to the already heavily loaded rear tire and the car would progressively carry a larger proportion of the car weight on the outboard rear wheel, increasing its slip angle and eventually pushing the car into lift-off oversteer.

Chevrolet had considered adding a front anti-roll bar for the original 1960 car, which would have shifted a significant part of this weight transfer to the FRONT outboard tire and reduced the rear slip angles considerably in severe cornering, but the extra cost ($6 per car is often cited) and confidence in the tire pressure differential adequately compensating for the inclination for oversteer led GM to delete the anti–roll bar from production models. This false economy was to come back to haunt GM later. The anti–roll bar did become available as an option in 1962, and was made standard finally in 1964. The 1964 rear suspension was modified considerably with a transverse leaf spring carrying much of the rear weight and vastly softer coil springs, in an effort to significantly reduce roll stiffness at the rear of the chassis. The redesigned 1965 suspension was a total solution, cutting the rear roll center down to half its previous height, reducing rear roll stiffness very significantly with fully articulated half-axles that offered constant camber on the rear tires in all driving situations. Although much is made of the 'jacking' (tendency for swing axle suspensions to go into very severe positive camber in extreme corners) and large camber changes generally during suspension travel in swing axle suspensions, the bias ply tires used at the time were very insensitive to camber and did not have very significant reductions in cornering power at high camber, unlike belted and radial tires which became commonplace later on.

Contemporary Volkswagens, Renaults, Porsches, and other rear-engined cars all used swing axles. As Corvair was designed to avoid terminal oversteer by using very low air pressure in the front tires, typically 15 to 19 pounds force per square inch, so that they would begin to understeer (increase slip angles faster than the rear) before the swing axle oversteer would come into play, this pressure was quite adequate for the very lightweight Corvair front end on the already quite wide tire. Owners and mechanics, either through ignorance of the necessity for this pressure differential between front and rear or thinking that the pressure was too low for the front, would frequently inflate the front tires to more "normal" pressures, thus ensuring that the rear of the car would oversteer. It should be mentioned that the Corvair is by no means unique in requiring dissimilar front and rear tire pressures for normal controllability; even the front–wheel–drive Cadillac Eldorado years later used very low REAR pressures (16 psi) to balance handling.

Of course, the bias ply tires used on automobiles in the 1960's were very sensitive to pressures proportionate to the weight they were carrying to ensure even wear- radial ply and bias belted tires that were adopted later are considerably less sensitive due to the bracing effect of the circumferencial 'belt'. With Corvair's ~40/60 weight distribution, pressures at much variance from GM's recommendation would have caused very uneven tire wear and a drastically shortened tread life. Carrying Chevrolet's suggested pressures not only provided very good handling, but would maximize tire life, and Corvair had a good reputation for tire life, often nearly double the OEM tire life expected of competitive makes. Modern pickup trucks and other vehicles with a very high weight bias invariably suggest significant tire pressure variances.

Although Nader possibly overstated the severity of the handling problems, as was later found by US National Highway Traffic Safety Administration investigators, Chevrolet made changes to the suspension: in 1964, adding a transverse leaf spring extending between the rear wheels to limit rear wheel camber change. In 1965 the Corvair got a state–of–the–art fully independent rear suspension closely resembling that of the contemporary Corvette, even sharing some components. These changes were, however, viewed by critics as Chevrolet's recognition of problems with the original design.

Modifications
Many sports car purists were more interested in the Corvair (particularly the 1965 and later cars) than in more conventional designs, such as the Ford Mustang, despite the latter's power advantage. From the first appearance of the Corvair, a large selection of high-performance equipment and modifications became available for it.

Ultra Van
The Ultra Van (or Ultravan) was a Corvair powered Motorhome that was produced from 1961-1971. Using an aircraft style monocoque body, its aerodynamic shape permitted the relatively low-output 80, 95 and 110 horsepower Corvair Engine to power it to speeds over 70 mph. Fuel economy was quite good for this type of vehicle, in the middle teens for miles per gallon- about double what comparable V8 powered standard motorhomes could muster. An all wheel independent suspespension, and spacious interior added to comfortable accomidations for the travelling family. Ultravans are well supported even today by a chapter in the Corvair Society of America (CORSA) who's motto is 'Whales on wheels' a reference to the unique bloated shape of the UltraVan.

Yenko Stinger
Don Yenko, who had been racing Corvettes, could not compete successfully against the Carroll Shelby Mustangs after they arrived on the scene; he therefore decided to race modified Corvairs, beginning with the 1966 model. As the stock Corvair did not fit into any of the SCCA categories, Yenko had to modify four-carburetor Corsas into "sports cars" by removing the back seat; in the process he would introduce various performance improvements. As the SCCA required 100 cars to be manufactured to homologate the model for production racing, Yenko completed 100 Stingers in one month in 1965. Although all were white, as the SCCA required for American cars at the time, there was a great deal of variety between individual cars; some had exterior modifications including fiberglass engine covers with spoilers, some did not; some received engine upgrades developing 160, 190, 220, or 240 hp (119, 142, 164, or 179 kW). All were equipped by the Chevrolet factory with heavy duty suspension, four speed transmission, quicker steering ratio, positraction differentials (50 with 3.89 gears, and 50 with 3.55 when Chevrolet dropped the 3.89) and dual brake master cylinders (the first application of this by Chevrolet, to become stock equipment the next year). The Stingers competed in Class D Production, which was dominated by the Triumph TR4, which was very quick in racing trim; however in its first race in January 1966, the Stinger was able to come in second by only one second. By the end of the 1966 season, Jerry Thompson had won the Central Division Championship and placed fifth in the 1966 Nationals, Dick Thompson, a highly successful Corvette race driver, had won the Northeast Division Championship, and Jim Spencer had won the Central Division Championship, with Dino Milani taking second place.

The next year, however, Chevrolet dropped the Corsa line, and the Monza line was not initially available stock with the four carburetor engine; the engine was eventually offered as a special performance option, however, along with the 3.89 differential. The Monza instrumentation, however, did not have a tachometer or head temperature gauges, which had to be separately installed. The SCCA, on the other hand, had relaxed its ruling regarding color, and the cars were available in red or blue. It is believed that only fourteen 1967 Stingers were built, but Dana Chevrolet, who distributed Stingers on the US West Coast, ordered an additional three similar cars to be built to Stinger specifications, but with the AIR injection system to meet California emissions laws, with Yenko's permission. A total of 185 Stingers are believed to have been built, the last being YS-9700 built for Goodyear Tire and Rubber Company as a tire test vehicle in 1969 – 1970.

Comedian, television star, and car enthusiast Tim Allen currently owns and races Yenko Stinger #YS-043.

John Fitch Corvair Sprint
Longtime roadracer John Fitch was particularly interested in the Corvair as the basis for a spirited road and track oriented car, due to its handling. The basic Sprint received only minor modifications to the engine, bringing it to 155 hp (116 kW), but upgrades to the shock absorbers and springs, adjustments to the wheel alignment, quicker steering ratio, alloy wheels, metallic brake linings, the obligatory wood-rimmed steering wheel (leather available for an additional $9.95) and other such minor alterations made it extremely competitive with European sports cars costing much more. Body options such as spoilers were available, but the most visually remarkable option was the "Ventop", a fiberglass overlay for the C-pillars and rear of the roof that gave the car a "flying buttress" profile.

Fitch went on to design and build a prototype of the Fitch Phoenix, a Corvair-based two-seat sports car, superficially resembling a smaller version of the Mako Shark based Corvette. With a total weight of 1,950 pounds (885 kg), even with a steel body, and with the Corvair engine modified with Weber carburetors to deliver 175 hp (130 kW), the car delivered spirited performance for $8,760. Unfortunately, the Traffic Safety Act of 1966 placed restrictions on the ability to produce automobiles on a small scale; this was followed by Chevrolet's decision to terminate production of the Corvair, which confirmed the end of Fitch's plan. He still retains the prototype however, and occasionally exhibits it at car shows. The car may be glimpsed briefly in the documentary film Gullwing at Twilight: The Bonneville Ride of John Fitch.

V8 Corvairs
The ultimate Corvair modification was replacement of the engine with a V8. As daunting as this might seem, two things made it possible: A radiator occupies the former trunk, in the front of the vehicle. However, the former engine compartment in the rear now is available as luggage space. A complete kit to adapt a Chevrolet small-block V8 to a Corvair was manufactured by a company named Crown Manufacturing, for $600. The resulting vehicle weighed only 2,750 pounds (1250 kg), compared to 3,700 pounds (1680 kg) for a small block Corvette, and possessed independent rear suspension of almost the same design. Crown's prototype with 350 hp (261 kW) Corvette engine recorded an elapsed time of 12.22 seconds and 105 miles per hour (169 km/h) in the quarter mile (402 m). An advantage of this modification is that the mid-engine design provides optimal handling characteristics for the road, as well as excellent drag strip traction without the need for slick or "cheater slick" tires as seen in front engine cars, let alone modifying the wheelbase as on the FX funny cars of the time. Although a few Corvairs have been modified to accept the Chevrolet big-block engine, the added size of the engine makes the work significantly more difficult, and the result, although a great performer, tends to be unreliable. Yenko Corvair YS99 was one of the 300 or so CORV8 conversions made. It is also possible to install a reverse rotation small block chevy in place of the flat six with many modifications.
 * 1) The Corvair engine rotated in the opposite direction from most other engines, so that if a V8 was placed in the rear seat area (the added weight of a V8 in the original location of the Corvair engine would be abominable to drive) and coupled to the front of the transmission via a supplied custom made clutch gear and input shaft, this would drive the car in the proper direction with four speeds forward and one reverse.
 * 2) The switch in 1966 to using standard Chevrolet Saginaw gear sets in the manual transmission could handle the torque of a V8.

Eshelman Golden Eagle
The first Eshelman Golden Eagle was an ordinary mid-1960s Chevrolet Corvair retrimmed with special emblems and other ornamentation and marketed through used-car dealers by Eshelman Motors Corporation of Baltimore, Maryland.

By 1967 the model was called the Eshelman Golden Eagle Safety Car and was based on the contemporary Chevrolet line, but now each Golden Eagle had a patented standard 15MPH impact-resistant "crash absorber" fashioned by incorporating each car's spare tire into the front bumper. Advertising claimed the cars were "Designed for the owner who has a special value for his life and the lives of his loved ones." Known Golden Eagle dealerships included the former Kislack Kar Sales in Houtzdale, Pennsylania and Plaza Motors in Niagara Falls, New York, but exact sales numbers are not known.

Dune Buggies
Corvair flat-six engines were a popular alternative to Volkswagen engines in dune buggy applications, and racing.