Pontiac Firebird 1970 庞蒂亚克火鸟

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The Pontiac Firebird is an automobile which was built by the Pontiac division of General Motors between 1967 and 2002. The Firebird was introduced the same year as the automaker’s platform-sharing model, the Chevrolet Camaro. This coincided with the release of the 1967 Mercury Cougar, which shared its platform with another pony car, the Ford Mustang.

Replacing the “Coke bottle” styling was a more “swoopy” body style, with the top of the rear window line going almost straight down to the lip of the trunk lid—a look that was to epitomize F-body styling for the longest period during the Firebird’s lifetime. The new design was initially characterized with a large C-pillar, until 1975 when the rear window was enlarged.

There were two Ram Air 400 cu in (6.6 L) engines for 1970: the 335 hp (250 kW) Ram Air III (366 hp (273 kW) in GTO) and the 345 hp (257 kW) Ram Air IV (370 hp (280 kW) in GTO) that were carried over from 1969. The difference between the GTO and Firebird engines was the secondary carburetor linkage which prevented the rear barrels from opening completely. Bending the linkage to allow full carburetor operation resulted in identical engine performance.

Curb weights rose dramatically in the 1974 model year due to the implementation of 5 mph (8.0 km/h) telescoping bumpers and various other crash and safety related structural enhancements; SD455 Trans Ams weighed in at 3,850 lb (1,750 kg) in their first year of production (1974 model year).

The 455 engine available in the second generation Firebird Trans Am was arguably the last high-performance engine of the original muscle car generation. The 455 cu in (7.5 L) engine made its first appearance in the Firebird in 1971 as the 455-HO, which continued through the 1972 model year. In 1973 and 1974, a special version of the 455, called the Super Duty 455 (SD-455), was offered. The SD-455 consisted of a strengthened cylinder block that included 4-bolt main bearings and added material in various locations for improved strength. Original plans called for a forged crankshaft, although actual production SD455s received nodular iron crankshafts with minor enhancements. Forged rods and forged aluminum pistons were specified, as were unique high-flow cylinder heads.

The 480737 code cam (identical grind to the RAIV “041” cam) was originally specified for the SD455 engine and was fitted into the “pre-production” test cars (source: former Pontiac Special Projects Engineer Skip McCully*), one of which was tested by both HOT ROD and CAR AND DRIVER magazines. However, actual production cars were fitted with the milder 493323 cam and 1.5:1 rocker ratios, due to the ever-tightening emissions standards of the era. This cam and rocker combination, combined with a low compression ratio of 8.4:1 advertised (7.9:1 actual) yielded 290 SAE net horsepower. It should also be noted that production SD455 cars did not have functional hood scoops, while the “pre-production” test cars did.*

Actual production cars yielded 1/4 mile results in the high 14 to 15.0 second/98 MPH range (sources: MOTOR TREND MAGAZINE, July ’73 and Roger Huntington’s book, AMERICAN SUPERCAR) – results that are consistent with a 3,850 pound car (plus driver) and the rated 290 SAE net horsepower figure. (An original rating of 310 SAE net horsepower had been assigned to the SD455, though that rating was based on the emissions non-compliant “pre-production” engines, as discussed above. That rating appeared in published 1973 model year Pontiac literature, which had been printed prior to the “pre-production” engines “barely passing*” emissions testing, and the last minute switch to what became the production engine. 1974 model year production literature listed the specifications of the production engine (290 SAE net horsepower).

A production line stock SD455 produced 253 rear wheel HP on a chassis dyno, as reported by HIGH PERFORMANCE PONTIAC magazine (January, 2007). This is also consistent with the 290 SAE Net horsepower factory rating (as measured at the crankshaft). Skip McCully verified that no production SD455s released to the public were fitted with the 480737 cam.* When asked about the compromises for the production SD455 engine, Mr. McCully responded, “Compression, camshaft, jetting, and vacuum advance.” He followed by stating that he would have preferred a compression ratio of 10.25:1, a camshaft with 041 valve timing, slightly richer carburetor jetting, and as much vacuum advance as the engine would tolerate.* (*May, 2005 issue of HIGH PERFORMANCE PONTIAC Magazine). Regrettably, that proved to be impossible due to the emissions regulations of the era.

1972 Pontiac Firebird Trans Am 455

During a 1972 strike, the Firebird (and the sister F-body Camaro) were nearly dropped.[9] Pontiac offered the 455 through the 1976 model year, but tightening restrictions on vehicle emissions guaranteed its demise. Thus, the 1976 Trans Am was the last of the “Big Cube Birds,” with only 7,100 units produced with the 455 engine.

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The 1974 models featured a redesigned “shovel-nose” front end and new wide “slotted” taillights. In 1974, Pontiac offered two base engines for the Firebird: a 100 hp (75 kW) 250 cu in (4.1 L) inline-6 and a 155 hp (116 kW) 350 cu in (5.7 L) V8. Available were 175 to 225 hp (130 to 168 kW) 400 cu in (6.6 L) V8 engines, as well as the 455 cu in (7.5 L) produced 215 or 250 hp (160 or 186 kW), while the SD-455 produced 290 hp (220 kW). The 400, 455, and SD-455 engines were offered in the Trans Am and Formula models during 1974

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The 1975 models featured a new wraparound rear window with a revised roofline and the turn signals were moved up from the valance panel to the grills which distinguished it from the previous year model. The Super Duty engine, Muncie 4-speed, and TurboHydramatic were no longer available in 1975. The 400 was standard in the Trans Am and the 455 was optional for both 1975 and 1976 models.

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In 1976, Pontiac celebrated their 50th Anniversary, and a special edition of the Trans Am was released. Painted in black with gold accents, this was the first anniversary Trans Am package and the first production Black and Gold special edition. In 1977, Pontiac offered the T/A 6.6 Litre 400 (RPO W72) rated at 200 hp (150 kW), as opposed to the regular 6.6 Litre 400 (RPO L78) rated at 180 hp (130 kW). The T/A 6.6 equipped engines had chrome valve covers, while the base 400 engines had painted valve covers. In addition, California and high-altitude cars received the Olds 403 engine, which offered a slightly higher compression ratio and a more usable torque band than the Pontiac engines of 1977.

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A distinctive, slant-nose facelift occurred in 1977, redone somewhat in 1979. From 1977 to 1981, the Firebird used four square headlamps, while the Camaro continued to retain the two round headlights that had previously been shared by both Second Generation designs. The 1977 Trans-Am Special Edition became famous after being featured in Smokey and the Bandit. Later on the 1980 Turbo model was used for   1971_pontiac_firebird-pic

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