The 1971 Corvette

The Overview

The 1971 Corvette is the 1970 again, and on purpose. The strike and the late 1970 launch left Chevrolet no time or appetite for change, so the body, the interior and the chassis carried over with a few details: an easier fuel-filler door, a lit shift quadrant for the automatic, amber parking-lamp lenses in the specifications (most cars still got clear lenses and amber bulbs), and the fiber-optic lamp monitors in their last year, missing from many late cars. The St. Louis plant, finally building one car for two years, used the breathing room to fix the fit and finish the magazines had been complaining about since 1968, and the 1971 is a better-built car than the two before it.

What changed was under the hood. Ed Cole, now president of General Motors, ordered every 1971 GM engine to run on 91-octane low-lead fuel ahead of catalytic converters, and the Corvette’s engines were detuned in weeks: the base 350 fell from 10.25:1 and 300 hp to 8.5:1 and 270, the solid-lifter LT-1 from 370 hp to 330 on 9.0:1, and the 454 LS5 from 390 hp to 365. The exception was the LS6, the cancelled 1970 LS7 reworked for low-lead fuel: aluminum heads, solid lifters, 9.0:1 compression and 425 hp, the last Corvette engine rated above 400 horsepower until the 2002 Z06. It cost $1,221 and 188 buyers paid it, 12 of them as the ZR2 package with the M22 gearbox, heavy-duty brakes and suspension and no radio or air conditioning. The ZR1 returned on the LT-1 for 8 cars.

Production recovered to 21,801, 14,680 coupes and 7,121 convertibles, the coupe now outselling the open car two to one, and the Turbo Hydra-Matic went into nearly half of them. Prices rose to $5,496 and $5,259. For buyers the 1971 is the last year of the LS6 and the big-block Corvette as a serious performance car, the second of three LT-1 years, and a cheaper way into a 1970-spec Shark than the 1970 itself; the LS6 and ZR2 are the blue chips, and the 1971 ZR2 convertibles are among the most expensive C3s ever sold.

The 1971 Corvette Story

The 1971 Chevy Corvette remains one of the least changed models in design (when compared to the preceding model year) in Corvette’s entire production history.

The United Auto Workers (UAW) labor dispute that occurred in May 1969, which had caused the 1969 model year to run over by two months, had also shortened production of the 1970 Corvette by over four months.

Because of this, it was decided by Chevrolet management that they should treat the 1971 model year as an extension of the 1970 line, which meant that the Corvette – for better or worse – would remain essentially unaltered between the two model years.

Because the production of the cars would remain virtually unchanged from 1970 to 1971, production lines in the St. Louis Corvette plant were able to work in earnest to produce a more trouble-free car. In fact, the (more than) 500 men and women that worked each shift at the Corvette plant were highly motivated to build a better machine, knowing that they were fortunate not to be part of the many facilities across the country that mass-produced “faceless utility cars”, but rather a well-respected, much sought after sports car. Vince Shanks, the plant manager of the St. Louis Corvette Manufacturing Plant, was quoted as saying “When you ask a guy where he works in St. Louis, he’ll tell you ‘Corvette’ rather than ‘Chevrolet.’ Every Corvette he sees on the road is one he’s worked on. That’s quite an incentive.”

The 1971 Corvette’s arrival also came in conjunction with a flurry of new federal regulations that forced manufacturers to reassess the types of cars they were producing.

In addition to the Federally sanctioned mandates on reducing exhaust emission outputs, Edward Cole (who was now president of General Motors) had decreed that all 1971 GM cars would be capable of running on fuel with a Research Octane Number (RON) no higher than 91 Octane.

According to Cole’s calculations, this octane rating was low enough for the fuel companies to begin marketing the lead-free regular gasoline needed to avoid fouling catalytic “reactors” (known as converters today) that were going to be required on automobile engines. This reduction in fuel octane rating would translate into a reduction in engine compression (now just 8.5:1) and horsepower (a mere 270 bhp in the stock 350 engine).

Somewhat surprisingly, these sanctioned emissions and fuel requirement changes didn’t only impact Corvette’s base engine. To the contrary, a notable reduction in compression – and power – was seen on almost all of the engines offered in the 1971 Corvette. The solid lifter, small block LT1 engine, which had boasted 370 horsepower in 1970, was now rated at a more modest 330 horsepower with a 9.0:1 compression ratio. The big-block engines also received the same treatment. The LS5 454 cubic inch big-block came equipped with 365 horsepower at 4,800 rpm, and a new aluminum-head big-block engine identified as the LS6 was rated at 425 horsepower at 5,600 rpm. Given the output numbers of these engines, there were few who would argue that the 1971 Corvette was weak, although most would agree that it was a far cry from the Corvettes that emerged in the unregulated era of muscle car performance.

Interestingly, the 1971 454 LS6 engine was actually a detuned version of 1970’s planned but cancelled 460 horsepower LS7. While the engines were fundamentally the same, the LS6 was developed to operate on low-lead, lower-octane fuel, giving it the clear marketing advantage over its never-to-be LS7 predecessor, despite its lower horsepower rating.

The LS6 engine featured aluminum heads, and its pistons were modestly domed, which helped it achieve the slightly higher 9.0:1 ratio. One unique feature for this high-performance big-block engine was that it could be ordered with an automatic transmission, although not when it was combined with the ZR2 package. Still, the option cost $1,220.70, and only 188 were ever sold. Even Duntov, who had pushed for the development of the LS6, had later been quoted in Car & Driver as saying, “Maybe I make mistake. Aluminum heads are expensive and that weight (reduction) doesn’t matter on the street.”

Still, it was the right kind of engine to lead the Corvette lineup, and that was where its real marketing value mattered most.

Because of Cole’s far reaching directive, Chevrolet engineers had only a matter of weeks rather than months to adjust all of their engines – and not just those for the Corvette. Because of this, very few changes were made to the 1971 Corvette – other than those made to the engines.

Did you know? The 1971 Corvette production specs called for the use of amber parking light lenses. However, most 1971 Corvettes came equipped with clear lenses and amber bulbs, which was a carry-over from the 1970 model year. Additionally, the 1971 Corvette included an optional custom interior trim package which included leather seat trim, wood-grain accents, and lower carpet trim on interior door panels, wood grain accents on the console and special cut-pile carpeting.

There were minor advances made, such as an easier-to-open fuel filler door, and an automatic transmission selector quadrant that illuminated during night time operation, but nothing that really separated the 1971 model from earlier years. However, the 1971 Corvette would be the last Corvette model to feature the fiber-optics light monitoring system, and it is believed that many late model 1971 Corvettes were actually manufactured without the fiber optics. (While not a notable change to the 1971 Corvette, the removal of the fiber-optic system allowed Chevrolet to make the optional anti-theft alarm system (RPO UA6) standard equipment for the 1972 model.)

For 1971, Chevrolet offered consumers not one, but two special purpose (racing) packages. The first of these was the RPO ZR1 package which utilized the aforementioned LT1 engine, and also included a heavy-duty, four-speed, close ratio transmission (RPO M22), heavy-duty power brakes, a special aluminum radiator, a metal fan shroud, a transistor ignition, and a revised suspension with special springs, shocks, spindle-strut shafts, and front and rear stabilizer bars (though it has since been determined that the 1971 ZR1 has appeared with and without rear stabilizers). When equipped with the ZR1 package, consumers were unable to include many of the more “luxurious” amenities available, including power windows, a rear window defroster, air conditioning, power steering, deluxe wheel covers, an alarm system, and any type of AM/FM radio.

The second special purpose package that Chevrolet offered was RPO ZR2. This second special purpose package was identical to the ZR1, except that instead of a small block LT1 engine, the ZR2 came equipped with the aforementioned 454 cubic inch LS6 engine. Like the ZR1, the ZR2 package also included the same ordering restrictions – namely none of the “creature comfort” amenities that were appealing to many consumers.

It may be for that very reason – or perhaps that combined with the substantial cost increase that each option carried with it - that so few of either performance package were ordered during that model year. In total, only eight Corvettes were ordered with the ZR1 option, and only twelve were ordered with the ZR2.

Beyond these items, the 1971 Corvette carried on much as its 1970 predecessor had. Pricing for the 1971 Corvette increased, though only modestly, to $5,259 for a convertible, and $5,496 for the coupe.

Production Volumes

With production now recovered from the UAW strike, sales of the 1971 Corvette improved, resulting in a total of 21,801 Corvettes sold for that model year, with the coupe taking a 2 to 1 sales lead over the convertible – a result which many believed was the result of the C3’s introduction of T-tops in 1968. Prior to that point, Corvette convertibles had actually dominated sales, but starting in 1969, more coupes than convertibles were sold with each model year that passed.

In 1971, the result was 14,680 coupes to just 7,121 convertibles – a fact that GM would take under serious consideration in the years to come, and also a fact that would lead to a shocking, and some consider controversial, decision for the 1976 model year.