Chevrolet Corvette C3 454/425 LS6
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Car producer : |
Chevrolet |
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Model: |
Corvette C3 454/425 LS6 |
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Year: |
1971 |
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Type: |
Coupe |
The third generation Corvette, patterned after the Mako Shark II concept car, was introduced for the 1968 model year and was in production until 1982. C3 coupes featured the first use of T-top removable roof panels. It introduced monikers that were later revived, such as LT-1, ZR-1, and Collector Edition. In 1978, the Corvette's 25th anniversary was celebrated with a two-tone Silver Anniversary Edition and an Indy Pace Car replica edition of the C3. This was also the first time that a Corvette was used as a Pace Car for the Indianapolis 500.
Engines and chassis components were mostly carried over from the C2, but the body and interior were new. The 350 cu in (5.7 L) engine replaced the old 327 cu in (5.36 L) as the base engine in 1969, but power remained at 300 bhp (224 kW). 1969 was the only year for a C3 to optionally offer either a factory installed side exhaust or normal rear exit with chrome tips. The all-aluminum ZL1 engine was also new for 1969; the special big-block engine was listed at 430-hp (320 kW), but was reported to produce 560 hp (420 kW) and propelled a ZL1 through the 1/4 mile in 10.89 seconds.
There was an extended production run for the 1969 model year due a lengthy labor strike, which meant sales were down on the 1970 models, to 17,316.[35] 1970 small-block power peaked with the optional high compression, high-revving LT-1 that produced 370 bhp (276 kW). The 427 big-block was enlarged to 454 cu in (7.44 L) with a 390 bhp (291 kW) rating. In 1970 Corvette Chief Engineer Zora Arkus Duntov applied the lessons learned from the all-conquering L88 to the small block Corvette, resulting in the race-ready ZR1. Although formally listed as a “Special Engine Package”, the ZR1 was in reality a small block version of the L88, with identical chassis preparation, brakes, cooling and accessory deletions. Produced from 1970 to 1972, the ZR1 was powered by the mighty LT1 solid lifter small block, which was fitted with a heavy duty L88 starter and a lightweight flywheel and mated to the famous Muncie M22 “Rock Crusher” 4-speed manual transmission. J56 Heavy Duty Brakes were used, as were transistorized ignition, a special aluminum radiator with surge tank and metal fan shroud, heavy duty springs and shock absorbers and larger diameter front and rear sway bars, all features of the L88. In keeping with its mission as a competition car, the ZR1 could not be ordered with power windows, power steering, air conditioning, a rear-window defogger, wheel covers, or a radio. Only 53 ZR-1's were built.
The third generation Corvette, patterned after the Mako Shark II concept car, was introduced for the 1968 model year and was in production until 1982. C3 coupes featured the first use of T-top removable roof panels. It introduced monikers that were later revived, such as LT-1, ZR-1, and Collector Edition. In 1978, the Corvette's 25th anniversary was celebrated with a two-tone Silver Anniversary Edition and an Indy Pace Car replica edition of the C3. This was also the first time that a Corvette was used as a Pace Car for the Indianapolis 500.
Engines and chassis components were mostly carried over from the C2, but the body and interior were new. The 350 cu in (5.7 L) engine replaced the old 327 cu in (5.36 L) as the base engine in 1969, but power remained at 300 bhp (224 kW). 1969 was the only year for a C3 to optionally offer either a factory installed side exhaust or normal rear exit with chrome tips. The all-aluminum ZL1 engine was also new for 1969; the special big-block engine was listed at 430-hp (320 kW), but was reported to produce 560 hp (420 kW) and propelled a ZL1 through the 1/4 mile in 10.89 seconds.
There was an extended production run for the 1969 model year due a lengthy labor strike, which meant sales were down on the 1970 models, to 17,316.1970 small-block power peaked with the optional high compression, high-revving LT-1 that produced 370 bhp (276 kW). The 427 big-block was enlarged to 454 cu in (7.44 L) with a 390 bhp (291 kW) rating. The ZR-1 special package was an option available on the 1970 through 1972 model years, and included the LT-1 engine combined with special racing equipment. Only 53 ZR-1's were built.
In 1971, to accommodate regular low-lead fuel with lower anti-knock properties, the engine compression ratios were lowered which resulted in reduced power ratings. The power rating for the 350 cu in (5.7 L) L48 base engine decreased from 300 to 270 horsepower and the optional special high performance LT1 engine decreased from 370 to 330 horsepower. The big-block LS6 454 was reduced from 450 to 425 bhp (317 kW), though it was not used in Corvettes for 1970; it was used in the Chevelle SS.
For the 1972 model year, GM moved to the SAE Net measurement which resulted in further reduced, but more realistic, power ratings than the previous SAE Gross standard.[ Although the 1972 model's 350 cu in (5.7 L) horsepower was actually the same as that for the 1971 model year, the lower net horsepower numbers were used instead of gross horsepower. The L48 base engine was now rated at 200 bhp (150 kW) and the optional LT1 engine was now rated at 270 bhp (200 kW).
