Getting the Lead Out: The 1970-1981 Chevrolet Camaro and the Rise and Fall of Leaded Gasoline

Pity the second-generation Chevrolet Camaro. Born late — a delivery fraught with complications — it was nearly snuffed out in adolescence. Although it survived to a ripe old age, it has never inspired the same nostalgia as its beloved 1967-1969 predecessor, perhaps because it arrived in the fray of one of the most contentious public debates of the 20th century: the battle over automotive emissions and the use of leaded gasoline. This is the story of the 1970-1981 Chevrolet Camaro and the rise and fall of leaded gasoline.

1973 Chevrolet Camaro Z/28 nose


The first-generation Chevrolet Camaro, Chevrolet’s belated response to the Ford Mustang, bowed in the fall of 1966 as a 1967 model. Although it won respect for its performance and muscular appearance, neither the Camaro’s looks nor its muscle were enough to let it seriously challenge the popularity of the Mustang. Dearborn’s “pony car” regularly outsold the Camaro (and its F-body sister, the Pontiac Firebird) by a considerable margin. Before its first model year was over, however, Hank Haga’s Chevrolet Styling Studio 2 was already at work on the second-generation Camaro.

The new Camaro was planned for the 1970 model year, which would ordinarily have put it on sale in the fall of 1969. As it happened, the new car didn’t appear until February 26, 1970, around five months late. There is a popular assumption that the delay was caused by labor issues — GM was at war with the United Auto Workers union (UAW) between 1969 and 1972 and there were several lengthy strikes during this period. The real reason was a serious problem with the dies used to make the new car’s complex rear quarter panels. The panels were splitting or wrinkling in early tests, forcing Fisher Body Die Engineering (the one-time independent coachbuilder that manufactured most of GM’s auto bodies) first to modify, then to completely redesign the dies. That in turn forced GM to keep the 1969 Camaro in production for an extra four months. Chevrolet had to scramble to draft expensive and complicated short-term agreements with suppliers, who already stopped producing parts for the outgoing car. All told, the delays cost GM millions of dollars, beyond the already high costs of introducing a new model.

1970 Chevrolet Camaro Z28 front
These early 1970 Chevrolet Camaros (both 70 1/2 models) have the popular Rally Sport option, which added driving lights inboard of the headlamps and removed the center grille bar and overriders, substituting a more protruding plastic nose clip with small “bumperettes” on either side of it.

1973 Chevrolet Camaro Z/28 head-on view
This is a 1973 Chevrolet Camaro with a reinforced front bumper (not immediately obvious) to meet federal requirements for 5 mph (8 km/h) crash protection. If this is a real ’73 Z/28, it has the 245 (net) horsepower (183-kW) L-82 engine; in any case, this car has Turbo Hydramatic automatic transmission.

When the second-generation Chevrolet Camaro finally did appear, it made a tremendous splash. It was one of the most radical-looking new designs the industry had seen since the excesses of 1959.

Unlike the Mustang, whose successive revamps from 1964 to 1973 represented a steady evolution of the original concept, the new Camaro was an almost complete stylistic break with its predecessor. The first Camaro, as we have previously seen, evolved from the “Super Nova” concept car of the early sixties. It essentially married the stylistic philosophy of the second-generation Chevrolet Corvair (1965-1969) with the short-deck, long-hood proportions popularized by the Mustang; park a 1967 Chevrolet Camaro next to a post-1965 Corvair and the family resemblance of their basic body shapes is readily apparent. The new Camaro looked more like something from Italy than Detroit. It featured a curvaceous nose and gaping grille that recalled early-sixties Ferrari or Maserati GT cars, particularly on Rally Sport models, which had no bumper ahead of their grille openings.

Under the skin, the new F-body was much more familiar. It was about two inches (51 mm) longer and slightly wider and lower than the 1969 Camaro, but it was structurally very similar. It shared the first-generation car’s semi-monocoque construction, with a separate front subframe carrying the engine and front suspension. Suspension design was substantially the same as before, as were most of the powertrain choices. Front disc brakes were newly standard, but the four-wheel discs that had been available on a very limited basis in 1969 were gone. The new Camaro was almost 200 pounds (90 kg) heavier, thanks to the addition of new side-guard door beams, as well as the more complex inner body stampings necessary for its curvy shape.

The high-performance Z/28 option package returned for 1970, but Chevrolet abandoned the earlier Z/28’s high-strung 302 cu. in. (4,942 cc) engine in favor of the new 350 cu. in. (5,733 cc) LT-1. The LT-1, shared with the Corvette, was rated at 360 gross horsepower (268 kW), about as a strong as the underrated 302, but far more tractable. It could now be ordered with automatic transmission, whereas first-gen Z/28s required a four-speed manual. A big-block V8 remained optional on other Camaros. Chevrolet still called the big Turbojet V8 a “396,” but it was now actually 402 cubic inches (6,587 cc), rated at 350 gross horsepower (261 kW). Chevy briefly announced that the Camaro would offer the big 454 cu. in. (7,443 cc) LS-6 engine offered in the 1970 Chevelle SS, rated at a whopping 450 gross horsepower (336 kW), but it never actually went into production.

1973 Chevrolet Camaro front 3q
Like the first-generation Chevrolet Camaro (and the Mustang), the second-generation Camaro had exaggerated long-hood, short-deck proportions, which gave it a muscular look. Note the flared front wheel wells: the second-generation Camaro’s front tread width was 1.6 inches (41 mm) wider than before, although overall width was only 0.4 inches (10 mm) greater. With fat, F60-15 tires, standard on Z/28s, the Camaro handled well by the standards of its era, although its grip can be matched by many modern economy cars. Its brakes were also marginal for the car’s weight, fading prodigiously in hard use.

The 1970 Chevrolet Camaro was just about as fast as its predecessor despite its extra weight. In May 1970, Car and Driver put its well-prepared automatic Z/28 across the quarter-mile line (402 meters) in the low 14-second range with a trap speed of slightly over 100 mph (161 km/h); Motorcade‘s Dave Epperson managed similar figures. That was excellent performance, but the bottom was about to fall out.


About nine months after the Camaro’s belated debut, the U.S. Congress unanimously passed the Clean Air Act of 1970. The Clean Air Act empower the recently created Environmental Protection Agency (EPA) to set and enforce standards for air pollution. The federal government had begun setting limits on automotive emissions for the 1968 model year, two years after the state of California initiated its own, more-stringent standards. The Clean Air Act called for a 90% reduction in automotive emissions by 1975. It also reopened a very old can of worms: the use of lead in gasoline.

To understand the history of leaded gasoline, we must examine some of the basic engineering concepts involved.

One of the most effective ways to improve both an engine’s specific output (its power per unit of displacement) and its specific fuel consumption (fuel burned per unit of power produced) is to increase its compression ratio. A four-stroke engine, like that used in most automobiles, compresses its air-fuel mixture before burning it. This compression has two effects. First, it increases the density of the mixture, packing oxygen and fuel molecules more tightly together, allowing more complete combustion. Second, it increases the energy of that mixture through adiabatic heating, allowing more energy to be extracted from it when it burns. A high static compression ratio (the ratio of the swept volume of each cylinder and combustion chamber when the piston is at bottom dead center — its lowest point — to the combustion chamber volume when the piston is at top dead center — its highest point) gives more power. Because it promotes efficient burning, a high compression ratio also improves fuel economy. For those reasons, the auto industry — spearheaded by General Motors — has long been enthusiastic about high-compression engines, like the high-revving LT-1.

1973 Chevrolet Camaro side view
Like the first-generation F-body, the second-generation Chevrolet Camaro was a monocoque aft of the cowl, with a rubber-isolated subframe carrying the engine, front suspension, and forward sheet metal. At 188 inches overall, it’s about 2 inches (50 mm) longer than the ’69 and 3.4 inches (86 mm) longer than the ’67-’68.

One problem with raising an engine’s compression ratio is that it increases the risk of autoignition, also called detonation, knocking, or pinking. In a spark-fired engine, autoignition is uncontrolled detonation of the fuel mixture before or after the spark plugs fire, usually caused by hot spots in the combustion chamber. Autoignition can be extremely harmful to an engine — at its most severe, it can blow a hole in a piston. The extra adiabatic heating caused by higher compression makes autoignition more likely, which limits how much compression ratios can be safely raised.

GM first became interested in higher compression ratios in the wake of World War 1. At the time, many experts feared that U.S. oil reserves would not be enough to keep up with the expected growth of oil use. They projected shortages by the late 1940s that would force the U.S. to buy much of its oil overseas. To guard against this possibility, GM explored various means of improving engine efficiency. High-compression engines were particularly attractive because they increased both fuel efficiency and power, but detonation remained a daunting obstacle.


Charles Kettering, who became head of GM’s research division in 1919, suggested an alternative. Kettering was aware that certain fuels were more resistant to detonation than others, and he had already worked with the U.S. Army and Bureau of Mines on the prospect of creating anti-knock fuels that would allow existing engine designs to use higher compression ratios.

Kettering’s staff developed a scale for measuring the knock resistance of a fuel, based on the properties of two of the hydrocarbons commonly found in gasoline. Heptane (n-Heptane) had poor knock resistance, so pure heptane was set as the zero point of the scale. Iso-octane (2,2,4-Trimethylpentane) had good knock resistance, so it was given a value of 100. The knock resistance of any given fuel was measured in terms of its octane rating (or octane number), determined by comparing its knock resistance to a mixture of pure heptane and pure iso-octane. If a fuel had the same knock resistance as a blend of 90% iso-octane and 10% heptane, for example, it was assigned an octane number of 90. (This doesn’t mean that the fuel actually contained those percentages of those specific hydrocarbons, just that it has the same resistance to autoignition as such a blend. Also, since some substances have knock resistance higher than iso-octane or lower than heptane, it’s entirely possible to have an octane rating lower than 0 or higher than 100.) Kettering’s challenge was to find a practical, affordable way to raise that octane number.

1973 Chevrolet Camaro front high
The Chevrolet Camaro’s Z/28 package was an option package, not a model, costing $598.05 in 1973 (down from $766 the year before). In 1973 the package included the L-82 engine, sport suspension, 15-inch wheels, dual outside mirrors, and a black-painted grille. The twin stripes, commonly associated with the Z/28 since 1967, were actually an additional option, RPO D88, costing $77. The Z/28 package was discontinued after 1974 and did not return until 1977.

GM’s interest in boosting the octane of gasoline was by no means a purely sporting one. In the 1920s, the oil company E. I. Du Pont de Nemours owned 35.8% of GM’s stock, and the two companies shared board members. If Kettering could find an economical fuel additive, it could be exceedingly profitable for both GM and DuPont.

With that in mind, it becomes more apparent why Kettering’s superiors rejected one of the most obvious octane boosters: ethyl alcohol. Ethanol has an octane rating of 129 RON (about 116 pump octane), which is substantially better than iso-octane. Although ethanol has significantly less thermal energy than gasoline, a high-compression engine running an 80/20 blend of gasoline and ethanol will still be more efficient than a lower-compression engine burning pure gasoline. Furthermore, since ethyl alcohol is produced by fermenting sugar, it is a renewable resource. Even in the 1920s, scientists were justifiably concerned about the dangers of diverting food crops to produce fuel, but Kettering saw great promise in work being done on converting cellulose into fermentable sugars, allowing ethanol to be produced from waste products like corn husks.

The problem, as far as GM and DuPont were concerned, was that GM could hardly patent ethanol, which greatly limited their profit potential. Moreover, during the era of Prohibition, storing or transporting large quantities of alcohol involved some uncomfortable legal gray areas. Kettering’s superiors ordered him to concentrate on finding a “low-percentage” additive, something that could be added in small amounts to gasoline to boost its octane number — and something that GM could patent and control.

After a lot of surprisingly unscientific trial and error, Kettering and his assistant discovered that a formulation of tetraethyl lead (TEL) greatly improved knock resistance when added to gasoline. TEL was easier to transport and easier to store than alcohol, which absorbs water (to say nothing of the potential hijacking and pilfering encouraged by Prohibition and the Volstead Act). Better yet, TEL’s use as a motor fuel additive could be patented.

NeverNox pump 2008 BeauB CCBY20Generic
A vintage sign for one of the many gasolines to use Ethyl TEL as an anti-knock additive. (Photo © 2008 Beau B; used under a Creative Commons Attribution 2.0 Generic license)

General Motors began selling tetraethyl lead as a fuel additive in early 1923. In 1924, GM formed a consortium with Standard Oil (the predecessor of the modern Exxon-Mobil Corporation) called the Ethyl Corporation, which sold high-octane leaded gasoline under the trade name “Ethyl.”


The problem with TEL is that lead is very poisonous, a potent neurotoxin. Members of Kettering’s own staff suffered from lead poisoning and 17 workers at the new TEL production facilities died of lead poisoning between 1923 and 1925. The result was a public outcry that led to a temporary halt of Ethyl production and an investigation by the Public Health Service. The PHS report, issued in late 1925, concluded that there were insufficient grounds to ban the use of tetraethyl lead in gasoline, although the report acknowledged that its conclusions were based on limited data and recommended further study.

Despite that mild warning, the Surgeon General approved the resumption of leaded gasoline production in January 1926. The PHS report was heavily criticized by other public health advocates, including Dr. Yandell Henderson of Yale University and Alice Hamilton of the Harvard Medical School. The impartiality of the Surgeon General’s decision was called into question by the fact the Secretary of the Treasury, under whose auspices both the Surgeon General’s office and the Public Health Service operated in those days, was Andrew Mellon, who personally owned a controlling interest in Gulf Oil, which had recently signed an exclusive contract with the Ethyl Corporation to distribute leaded gasoline in the southeastern U.S.

TEL warning sign near a leaded gasoline pump, copyright 2008 Joe Mabel CCBYSA30 Unported
Warning notice at a gas station in Lynnwood, Washington. (Photo © 2008 Joe Mabel; used under a Creative Commons Attribution-ShareAlike 3.0 Unported license)

Ethyl was soon added to more than 90% of American gasoline. Its safety was taken for granted to the extent that in 1936, the Federal Trade Commission issued an order prohibiting Ethyl’s competitors from criticizing or challenging Ethyl’s product as dangerous or unhealthy.

Meanwhile, the amount of lead used in gasoline continued to increase. At the end of the war, the auto industry — again led by GM — pushed the petroleum industry to offer even higher-octane gasoline for civilian use, allowing the development of a new generation of powerful V8 engines. As a result, by the late 1950s, the TEL content of premium gasoline reached as much as 4.25 grams per gallon (0.89 grams/liter).

By the 1950s, some scientists had begun to link the deleterious effects of high levels of lead contamination, both from the used of leaded paint and the widespread use of leaded gasoline, to a sobering array of health problems, particularly among children, including low IQ, mental retardation, and learning disabilities. By the early 1970s, some U.S. public health officials characterized it a public menace.

Automakers and oil companies strenuously denied any causative relationship between leaded gasoline and such health problems. Nonetheless, in 1962, GM and Standard Oil divested themselves of the Ethyl Corporation, arranging its leveraged buyout by Albemarle Paper. Their patent on TEL had expired in 1947, which had curtailed Ethyl’s margins somewhat, but reporter Jamie Kitman, who wrote extensively on the history of leaded gasoline for The Nation in 2000, speculated that the corporation’s one-time parents may have wanted to distance themselves from a potentially disastrous product liability issue.

1973 Chevrolet Camaro rear 3q view
The second-generation Chevrolet Camaro’s broad sail panels, with no rear quarter windows, did nothing for rear visibility. Unlike the first-generation car, the second-generation Camaro was never offered as a convertible. This car appears to be a 1973 Camaro, but it has the raised Z/28 emblem of a 1971 or 1972 car (replaced by a foil decal on the ’73s) and the chrome exhaust tips of a ’71 (dropped in ’72). The spoiler is from a post-1974 car; although spoilers were optional as RPO D80, the 1973 spoiler didn’t wrap around the fenders. This car is also missing the corresponding front spoiler that was included with RPO D80.


By the late 1960s, there was a renewed movement to eliminate the use of lead in gasoline. In 1969, U.S. Secretary of Health, Education, and Welfare (HEW) Robert Finch proposed that the major oil companies begin phasing out leaded gasoline, starting in the summer of 1971. To the shock of nearly everyone in the industry, GM president Ed Cole made a similar proposal at a Society of Automotive Engineers talk in January 1970. In March, Cole announced that GM would reduce the compression ratios of its engines to make them compatible with lead-free regular gasoline starting with the 1971 model year.

Around the same time, Henry Ford II, chairman of Ford Motor Company, sent a letter to 19 major petroleum companies asking them to begin offering lead-free fuels. Leaded gasoline, whose use had, even five years earlier, been taken completely for granted, was suddenly on its way out.

Inevitably, automakers continued to deny any connection between their requests for lead-free gasoline and the health concerns about TEL, insisting that there was no substantive evidence that the small amounts of lead in gasoline represented a hazard. Instead, they maintained that the phase-out was a precursor to the adoption of catalytic converters to meet upcoming California and federal emissions standards. Leaded gasoline was incompatible with catalytic converters, destroying the effectiveness of their active components by fouling them with lead deposits.

Meanwhile, the petroleum industry (including the Ethyl Corporation itself) began a massive PR campaign to protest that “unleaded” gasoline was neither necessary nor cost-effective. Ethyl executives found no support from General Motors, which kept its promise of lowered compression ratios. For the 1971 model year, even the high-winding Chevy LT-1’s compression dropped from 11.0:1 to 9.0:1.

1973 Chevrolet Camaro dashboard
This 1973 Chevrolet Camaro has the steering wheel of the new Type LT, a luxury-oriented model introduced for 1973, but it is not a Type LT — it doesn’t have the LT’s woodgrain dashboard trim, “blackout” (i.e., de-chromed) exterior trim, or concealed windshield wipers. It does have the optional full instrumentation, standard with Type LTs and an $82 option (RPO U14) without it. You could order the Z/28 package with the Type LT, which cost $389 more than a standard V8 Camaro Sport Coupe, and accounted for about a third of total Camaro sales that year.

The effect of the reduction on performance was immediately apparent. Chevrolet claimed the reduced compression ratio cost the LT-1 only about 15 net horsepower, but testers were skeptical. Car and Driver‘s May 1971 test of a 1971 Chevrolet Camaro Z/28 found that its quarter-mile trap speed — an excellent measure of a car’s power-to-weight ratio — had dropped by nearly 7 mph (11 km/h) even though their test car was almost 100 pounds (45 kg) lighter than their 1970 tester; such a drop suggesting an actual loss of more than 40 horsepower (30 kW).

The trend would only get worse; for 1972, the LT-1 dropped to 255 net horsepower (190 kW). In April 1972, the best quarter-mile time Road & Track‘s automatic Z/28 could manage was the mid-15-second range, with trap speeds of about 90 mph (145 km/h). For 1973, the LT-1 engine was replaced by the L-82, with milder camshaft with hydraulic, rather than mechanical lifters. Rated 245 net horsepower (183 kW), the L-82 was now the Camaro’s most powerful engine — the 402 had been dropped after the previous season. It also had to move a heavier car; new 5 mph (8 km/h) bumper standards further inflated the F-body’s already substantial curb weight.

1974 Chevrolet Camaro nose
Federal safety standards led to the adoption of new, much more prominent bumpers on 1974 Chevrolet Camaros like this one, increasing overall length by about 7 inches (177 mm) over the ’73 model. The nose clip behind it was now fiberglass. The mass of the bumpers and their shock absorbers added more than 200 pounds (90 kg) to the Camaro’s curb weight, cutting further into its performance and gas mileage.


Editorials in the automotive press generally condemned the transition to low-lead and lead-free gasoline. (The simple fact that such fuels became universally known as “unleaded,” rather than “lead-free” — implying that lead was a natural component that was being removed, like caffeine from coffee — speaks volumes.) Few of the contemporary car magazines seriously examined the public health issues associated with lead contamination; many were already deeply critical of pollution-control measures and were hardly sympathetic to the catalytic converter argument. All the automotive journalists saw was that their beloved Supercars were being systematically emasculated by politicians with no engineering knowledge or love of cars.

Overweight, increasingly underpowered, and hit with soaring insurance premiums, the unfortunate second-gen Camaro was further impacted by the ongoing conflict between GM and the UAW. A lengthy work stoppage at the Camaro plant in Norwood, Ohio, crippled production for the 1972 model year, reducing total output by almost 40,000 units. The cost of that loss was compounded when more than a thousand completed cars had to be scrapped after their delayed production made them too late to be sold as 1972 models; they did not meet the emissions or safety standards for the 1973 model year.

1974 Chevrolet Camaro headlight
In 1974, the Chevrolet Camaro got a facelift that included recessed, “sugar scoop” headlamps. The Type LT, starting at $3,380.70, accounted for about 49,000 sales, a little under a third of the 151,000-odd Camaros sold for 1974.

In the face of these problems, GM looked at the shrinking sales of the entire sporty car market and seriously considered dropping both the Camaro and its Firebird sibling. GM executives were hardly the only ones considering cutting their losses; AMC and Chrysler would drop their pony cars after 1974, while Ford reinvented the Mustang as the Pinto-based Mustang II. Nevertheless, GM finally decided to spare the Camaro the ax, apparently spurred by a grassroots campaign both inside and outside the company.

The F-body was mildly restyled for 1974, neatly incorporating the required new front and rear crash bumpers. Sales began to pick up nicely. Even though performance continued to erode, the Camaro and Firebird remained popular and profitable enough to last through 1981.


The battle over lead, however, was far from over. In 1972, when the EPA announced its intention to regulate the lead content of gasoline, the Ethyl Corporation promptly sued the agency. When regulations calling for a progressive phase-out of TEL were issued in 1973, Ethyl sued again. Their claims were rejected by a U.S. District Court of Appeals in 1976; the U.S. Supreme Court declined to hear the case. The Reagan administration attempt to roll back the lead phase-out in 1981, but political pressure forced them to relent the following year. Facing the loss of their U.S. business, Ethyl and its rivals began aggressively promoting TEL abroad.

Leaded gasoline for automotive use had been all but eliminated in the United States by 1986. Its use in street cars was formally banned at the end of 1995. The European Union finally banned leaded gasoline for passenger-car use in 2000, but leaded petrol remains in common use in many nations around the world, particularly in Africa and the Middle East. Non-passenger-car use of leaded gasoline has been slower to fade. Leaded racing fuel remained in general use until NASCAR finally adopted unleaded gas in early 2007. Aviation gasoline, meanwhile, continues to use TEL, although the most common avgas is now 100 octane “low-lead” fuel with about 2 grams of lead per U.S. gallon, much less than the 130-octane “highly leaded” gasoline previously used. Environmental groups are pressuring the EPA to mandate the removal of lead from aviation gasoline, but as of this writing, no phase-out has yet been announced.

1974 Chevrolet  Camaro side
The 1974 Chevrolet Camaro had a number of one-year-only features: It was the only big-bumper Camaro to retain the original rear window, which was replaced with a wrap-around design the following year in an effort to improve the dismal rear visibility. Note the concealed windshield wipers, which sit behind the trailing edge of the hood — this was a standard Type LT feature.

Although the health effects of lead in gasoline have abated noticeably, they may never disappear completely. More than 7 million tons of lead were burned in America between 1923 and 1986. Lead doesn’t break down or decay and it’s so pervasive that it will never be entirely gone. Still, there have been significant reductions in average blood-lead levels since the phase-out. The EPA estimates that the average level of lead in the blood of Americans dropped 78% between 1978 and 1986. A 2007 Amherst College study links the reduced lead levels to concurrent decreases in the incidence of violent crime.

The adoption of unleaded fuels cost petroleum refiners billions of dollars. They dutifully passed those costs along to customers by adding to the price of each gallon of fuel sold. It took several years for unleaded premium fuels to be generally available and the price charged for high-octane unleaded is greater than for comparable leaded premium. Furthermore, some of the additives adopted as alternative octane boosters, such as MTBE, have proven to be toxic in their own right.

One of the concerns raised about the switch to lead-free gasoline was that lead deposits served to lubricate engine valves, saving manufacturers the cost of hardened valve seats. Real-world experience has shown that excessive valve seat wear is only an issue in highly stressed, high-performance engines and the amount of lead necessary to prevent wear is much lower than the amount typically founded in even “low-lead” gasoline. Furthermore, that potential problem is balanced by greater wear in other areas. Leaded gasoline — and the binding chemicals, such as ethylene dibromide (EDB), added to keep lead deposits from building up on engine components — promotes spark plug fouling, cylinder bore wear, piston ring degradation, and corrosion of the exhaust system. EDB is also a carcinogen and has been linked to the degradation of the ozone layer.

1974 Chevrolet Camaro hood scoop
Although this is definitely a 1974 Chevrolet Camaro, the hood and its prominent hood scoop are taken from a 1980 or 1981 car. It was theoretically functional: A solenoid opened the trap door at the rear of the scoop to admit cool outside air to the engine. Since this is not a Z/28, it has one of the other 350 cu. in. (5,733 cc) V-8s; if it was originally a California car, that probably means the LM-1, with 160 net horsepower (119 kW) and 270 lb-ft (365 N-m) of torque, a $46 option. This car has Turbo Hydramatic.

What about the poor, beleaguered second-generation Camaro? Ironically, its popularity at the time has done no favors for its reputation today. Although the Camaro was never very common outside the U.S., if you’re an American of a certain age, the chances are that you owned one, or knew someone who did. Sheer ubiquity soon dulled the impact of styling that seemed so fresh and daring in the spring of 1970. By the time its replacement bowed in the fall of 1981, many people were more than ready to forget it and the era of inflation, gas rationing, and controversy in which it appeared.

The early (1970-1972) cars have their fans, to be sure, but they have never been as desirable as the first-generation Camaro, and probably never will be. It’s a shame — had the Camaro appeared before the smog and safety controversies, it would probably be considered a classic like its predecessor.

Sometimes, history has no mercy for those born in the wrong place at the wrong time.

# # #


Our sources for the history of leaded gasoline included Jamie Kitman’s lengthy essay “The Secret History of Lead,” The Nation 20 March 2000 issue of The Nation, www.thenation. com/ doc/20000320/kitman/single, accessed 30 May 2008; papers by William Kovarik, Ph.D., reprinted on his website: “Leaded gasoline: history and current situation,” n.d., www.radford. edu/~wkovarik/ethylwar/, accessed 30 May 2008; “Ethyl: The 1920s Environmental Conflict Over Leaded Gasoline and Alternative Fuels,” 26 March 2003, www.radford. edu/~wkovarik/papers/ethylconflict.html, accessed 30 May 2008; “Henry Ford, Charles Kettering, and the ‘Fuel of the Future,'” Automotive History Review #32 (Spring 1998), pp. 7-27, www.radford. edu/~wkovarik/papers/fuel.html, accessed 30 May 2008; “Charles F. Kettering and the 1921 Discovery of Tetraethyl Lead In the Context of Technological Alternatives,” originally presented to the Society of American Engineers Fuels & Lubricants Conference, Baltimore, MD, 1994, revised 1999, www.radford. edu/~wkovarik/papers/fuel.html, accessed 30 May 2008; Jessica Wolpaw Reyes, “Environmental Policy as Social Policy? The Impact of Childhood Lead Exposure on Crime,” National Bureau of Economic Research (NBER) Working Paper No. 13097, www.nber. org/papers/w13097, issued May 2007, accessed 1 June 2008; and Maurice Hendry, “Hillbilly Genius: ‘The Great Boss Ket,'” Special Interest Autos #51 (June 1979), pp. 20-27. We also consulted John Ethridge, “Gettin’ the Lead Out,” Motor Trend Vol. 22, No. 5 (May 1970), pp. 48-50, as a representative example of the automotive press’s reaction to the removal of lead from gasoline.

Sources on the 1970½-1981 Chevrolet Camaro included the Camaro Research Group website, “Primary Research and Restoration Data for First-Generation Camaros,” ed. Rich Fields, 1998-2008, www.camaros. org/index.shtml, accessed 30 May 2008; Mike Maciolak, Camaro Model Info, 2006, www.nastyz28. com/ index.php?page=camarofacts, accessed 30 May 2008; and the following vintage road tests: Ron Wakefield, “1970 Camaro & Firebird: Chevrolet & Pontiac versions of a new American GT, plus a facelifted Corvette for 1970,” Road & Track March 1970, reprinted in Firebird and Trans-Am Muscle Portfolio 1967-1972, ed. R.M. Clarke (Cobham, Surrey: Brooklands Books Ltd., 1998); “Chevrolet Camaro: The Z/28 version would be every bit as much at home on the narrow, twisting streets of Monte Carlo as it is on Interstate 80,” Car and Driver May 1970; “1970 Chevrolet Camaro,” Road & Track May 1970; Dave Epperson, “Zapped by a Z28 Camaro,” Motorcade May 1970; “New and Improved: The Camaro SS approaches GT status,” Road Test August 1970; “Chevrolet Camaro Z28: Underneath last year’s smooth exterior beats 1971’s low-compression engine,” Car and Driver May 1971; and “Camaros for Everything: An engineered guide through a thicket of options for luxury, performance or combinations thereof,” Road & Track April 1972, all of which are reprinted in Camaro Muscle Portfolio 1967-1973, ed. R.M. Clarke (Cobham, Surrey: Brooklands Books Ltd., 1992).


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  1. As compression ratios of engines increased, so did gasoline octanes. In the mid-1950s, premium gasolines had octane ratings of 96 and jumped to 98 by 1957-58 as compression ratios hit the 10 to 1 level and higher. Some oil companies introduced “superpremium” grades of 102 octane including Golden Esso Extra (in a gold pump 1956-61), Gulf Crest (the juice in the purple pump, 1957-61), and Chevron Custom Supreme (in the white pump, 1959-70) and of course, Sunoco 260 – which was the top of their 8-grade Custom Blended line.
    Most oil companies stuck with only two grades of gasoline (regular and premium) and competed with the superpremiums by increasing their “premium” gasoline octanes to 99-100 octane including Super Shell, Texaco Sky Chief, Phillips 66 Flite Fuel, Mobil Premium, Royal 76, Sinclair Dino Supreme, DX Super Boron, etc.

    Esso and Gulf discontinued their superpremiums in late 1961 due to low sales and simply increased the octanes of their premium gasolines Esso Extra and Gulf No-nox to within 1 or 2 octanes of Golden and Crest, with Esso replacing Golden with a mid-grade Esso Plus and Gulf repainting the purple pumps blue for its new subregular Gulftane.

    Then there were additives and promos of these high-octane premiums including Shell’s TCP and Platformate, Texaco’s Sky Chief with Petrox that Jack Benny was persuaded to put in his Maxwell to save him money (I’ll try a gallon), and Nickel Compound in Sinclair Dino Supreme, along with Esso’s “Put A Tiger in Your Tank” and Mobil’s “Detergent Gasoline” that cleaned carburetors, PCVs and whole fuel systems.

    Gulf stations during 1966-67 gave away free orange “Extra Kick Horseshoes” to motorists who purchased “No-nox” gasoline that were placed on the bumpers of cars. Esso (Enco in the central and west) stations gave away free tiger tails that were tied to gas tank fillers.

    And regular gasoline was not exactly “wimpy” in octane, either, as the cheaper fuels rose in octanes from about 91 from 1956-58 to 94 by 1965-66.

    1. Thanks for the details.

      It’s worth noting — as you’re probably already aware (but some other readers may not be) — the octane numbers are all research octane numbers, and as such don’t correspond directly with the pump octane ratings found on modern U.S. gas pumps. Pump octane is an average of the research octane number and the motor octane figure, so if sold from a modern pump, 94 RON gasoline would be rated less than 94 octane.

      Also, while different manufacturers have promoted it to different degrees over the years, all modern gasoline (and motor oil) does contain detergent. They don’t necessarily used the same detergents, or the same amounts, but it has been universal for some years.

  2. That is correct about the change in gasoline octane measurements from “Research” in the 1960s to today’s “Pump” octane is somewhat similar to the changes in engine horsepower measurements from the “gross” figures of 1971 and earlier on a dynometer without mufflers, accessories and emission equipment, to the “net” ratings of 1972 and later that were based on an engine as “installed” in a vehicle with exhaust system, accessories and emission controls installed.

    Today’s 87 “Pump” octane unleaded regular is the same fuel as the 91 “Research” octane fuel that was recommended in the 1971 Camaro owner’s manual. Similar spreads of 4-5 octane differences in fuels between pump and research exist for mid-grade unleaded – 89 Pump octane or 93 Research octane (just slightly below the 94 research octane for regular-grade fuel in 1971) and 93 Pump octane unleaded premium would be 97-98 research octane, or just slightly below the 99-100 research octane of leaded premium in that era.

    Another fact to consider. While almost all oil companies went to lead to increase gasoline octane in the 1920s and 1930s, American Oil Company continued to market its premium-grade gasoline – Amoco – as a lead-free fuel utilizing aromatics as an octane booster (American’s regular gas however was a leaded fuel as it was not as economical to sell the high-volume low-priced gasoline as a lead-free due to high production costs). Amoco was sold in several eastern and southern states since the 1910s. The lead free gasoline was marketed as simply Amoco or Amoco-Gas until 1961 when it was renamed American Super-Premium, and had reached a Research octane of 100 – similar to competitor’s leaded premium fuels – but sold about 1 to 2 cents higher per gallon.

    I would like to see or hear former muscle car owners back in the day who predominately used Amoco’s lead-free premium when those cars were new – and how well their vehicles held up in the face of reports that pre-1971 engines could suffer valve recession and other damage from predominant use of such fuel that continue to this day. I have heard of reports from owners of 50s and 60s cars with high-compression engines that used Amoco Super-Premium almost exclusively including Buicks, Cadillacs and Chryslers, stating that spark plugs were cleaner and lasted longer, and exhaust systems lasted much longer due to absence of corrosion caused by use of leaded gasoline.

    1. [quote]American Oil Company continued to market its premium-grade gasoline – Amoco – as a lead-free fuel utilizing aromatics as an octane booster[/quote]

      That’s very interesting — I didn’t know that.

  3. Actually the premium-grade lead-free gasoline marketed by the American Oil Company was called Amoco Super-Premium, not American Super-Premium as I implied – The lead-free Amoco product was marketed by the firm only in the eastern and southern U.S. while the rest of American’s marketing area throughout the nation (including its Standard Oil territory in the Midwestern U.S.) the premium-grade gasoline was called American Super-Premium, but that fuel was of the leaded variety as was American’s regular gas.

    Amoco’s lead-free premium would not spread to its Standard Oil territory until 1977, when it was it was rolled out to replace the leaded American high-octane juice – first to the larger markets including Chicago, Detroit, Milwaukee, Indianapolis, St. Louis, Denver, Kansas City and Minneapolis-St. Paul, and then the rest of the region.

    That fuel is still being marketed today by Amoco/Standard successor BP as Amoco Ultimate.

  4. In the third paragraph under “Changing Winds” you report that:

    >For the 1971 model year, the only GM engine requiring high-octane, leaded fuel was the high-strung LT-1 in the Corvette and Camaro. Even its compression ratio dropped from 11.0:1 to 9.0:1 — just a little too high for most available regular-grade fuels, leaded or not.<

    Sorry, but that statement is incorrect. All 1971 Chevrolet (and other GM divisions) engines were designed to run on regular, low-lead or no-lead gasoline with a Research Octane of 91 or higher – that was a Corporate mandate from the 14th Floor to all divisions. All engines from the four-cylinder Vega to the 330-horsepower LT-1 350 in Camaro Z-28 and Corvette and the 425-horsepower LS-454 offered in the Corvette.

    All of the car brochures from each of the GM divisions for 1971 included the above engine disclaimer of regular, low-lead or unleaded gasoline in the engine specification/availability charts, along with ALL of the owner’s manuals that came in the gloveboxes of GM cars and trucks.

    There was NOT a single engine in GM’s lineup for 1971 that required high-octane premium gasoline due to the corporate mandate requiring engines to use the lower-octane gasolines.

    Ford Motor Company and Chrysler Corporation did continue to offer some high-compression premium fuel engines for one last time in 1971.

    Ford’s high-compression engines included the 351 Cleveland 4-V, the Boss 351 Mustang engine, as well as all 429 and 460 cubic-inch V8s.

    Chrysler’s premium fuel engines for 1971 included the 340 Magnum offered in the compacts and ponycars, and the top musclecar engines for the Road Runner, GTX, Charger R/T and Super Bee incuding the 440 Magnum, 440 Six-Pack and the 426 Hemi.

    American Motors offered only one single premium fuel engine for ’71 – the 330-horsepower 401 V8 offered in the Javelin, Matador and Ambassador.

    Ford and AMC discontinued premium fuel engines entirely for the 1972 model year, while Chrysler barely slipped by with the 440 Six-Pack available in the Plymouth Road Runner and Dodge Charger, but only 12 cars were built with this engine – all of them very early in the model year in August and September, 1971. Sure this engine was listed in the ’72 brochures but was quickly discontinued shortly after the start of the year because it couldn’t meet the Federal emission regulations – and completely blackballed in California.

    For most of the ’72 model year, Chrysler’s hottest engines were the 240-horsepower 340 Magnum and the 280-horsepower 440 Magnum, both low-compression regular-fuel powerplants.

    1. I’ve amended the text. Thanks for the information.

  5. "By the 1950s, some scientists had begun to link the deleterious effects of high levels of lead contamination, both from the used of leaded paint and the widespread use of leaded gasoline, to a sobering array of health problems, particularly among children, including low IQ, mental retardation, and learning disabilities. By the early 1970s, some U.S. public health officials characterized it a public menace."

    "By the late 1960s, there was a renewed movement to eliminate the use of lead in gasoline. In 1969, U.S. Secretary of Health, Education, and Welfare (HEW) Robert Finch proposed that the major oil companies begin phasing out leaded gasoline, starting in the summer of 1971. To the shock of nearly everyone in the industry, GM president Ed Cole made a similar proposal at a Society of Automotive Engineers talk in January 1970."

    What I find an open question for debate is what factors contributed to the strong push for environmental and public health regulations of automobile emissions in the planning euphoria from the late ’60s until the early ’70s. Scientific knowledge of dangers of leaded gasoline seem to have grown for two decades before serious moves were made to regulate lead out of gasoline, just as did concern over smog had existed since after WWII before the federal government started making strong moves to cut gaseous emissions.

    In addition to thinking about social factors that might have pressured politicians to regulate the auto industry on pollution, it is also important to think about how the government’s regulatory efforts played out through the 1970s with shifting public and industry support. This is a fantastic look at the history of the removal of leaded gasoline in America, and I wonder what your thoughts are on the reasons why environmental regulation moved at different speeds through the 1960s, ’70s, and early 1980s. There are certainly many interesting stories to be told from these regulatory dramas.

  6. “The Reagan Administration attempted to roll back the lead phase-out” Does this sound familiar? This party will never stop subordinating public health to corporate profits.

  7. Not professing to be a fuel expert, but it was interesting while I was working over in Saudi Arabia that all of their gas stations (and I do mean all) had the same two fuel options of 91 and 95, whereas back in North America, fuel gets down to 87. I’m not sure if they were all lying or not, but it makes you wonder how they got that higher octane.

    1. Several things here. First of all, there’s no particular reason (other than cost) you can’t get unleaded fuel with more than 92-93 pump octane. Less than two miles from me, for example, is a gas station that sells 100 octane unleaded racing fuel — it’s expensive, but it’s legal and it’s available to anyone with the money to spend. I assume the reason 92-93 is the common upper end for pump gasoline is a trade-off of cost and demand, since most modern cars don’t need more than that. If another market favored higher compression ratios and didn’t commonly have knock sensors, it might be a different story.

      The other consideration is that the fuel stations in Saudi Arabia may not be advertising octane on the same scale used here. In the U.S., retailers are currently required to display the octane rating of their gasolines in "pump octane," which is the average of two different methods for measuring fuel octane: the research method and the motor octane method. In other parts of the world, it’s not uncommon to advertise fuel using only one or the other, more commonly the research octane number (RON). Because pump octane is an average, there is no way to know its research octane rating unless the company chooses to release either the motor octane or research octane ratings for their particular gasoline. However, the RON is usually higher than the pump octane rating, so 91 RON would probably give you something in the vicinity of 85 pump octane, while 95 RON would probably give you about 88-89 pump octane.

      My (admittedly unresearched) guess is that Saudi Arabian gas falls into the latter category, and you have cheap fuel that is actually somewhat lower octane than U.S. regular unleaded and a more expensive premium that falls somewhere between U.S. regular and mid-grade fuels.

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