Pontiac Firebird Trans Am

The Pontiac Firebird 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.

The vehicles were powered by various four-cylinder, six-cylinder, and V8 engines of different GM divisions. While primarily Pontiac-powered until 1977, Firebirds were built with several different engines from nearly every GM division until 1982 when GM began to discontinue engines it felt were unneeded and either spread successful designs from individual divisions among all divisions or use new engines of corporate architecture.

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 first made its appearance in 1971 as the 455-HO. In 1973 and 1974, a special version of the 455, called the 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. A 1967 GTO Ram Air camshaft with 301/313 degrees of advertised duration, 0.407 inch net valve lift, and 76 degrees of valve overlap was specified for actual production engines in lieu of the significantly more aggressive Ram Air IV style cam that had originally been planned for the engine (initially rated at 310 hp (230 kW) with that cam), but proved incapable of meeting the tightening emissions standards of the era. This cam, combined with a low compression ratio of 8.4 (advertised) and 7.9:1 actual resulted in 290 SAE net horsepower.

Production test cars yielded 1/4 mile times in the 14.5 second/98 MPH range in showroom tune – results consistent for a car with a curb weight of 3,850 pounds and the rated 290 SAE net horsepower figure some sources suggest was "under-rated," High Performance Pontiac magazine dyno-tested an SD and gave it 371 SAE net rating. During a 1972 strike, the Firebird (and the sister F-body Camaro) were nearly dropped. Pontiac offered the 455 for a few more years, 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.

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 hp (130 kW) to 225 hp (168 kW) 400 cu in (6.6 L) V8 engines, as well as the 455 cu in (7.5 L) produced 215 hp (160 kW) or 250 hp (190 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

The 1975 models featured a new wraparound rear window with a revised roofline. The Super Duty engines, Muncie 4-speed, and TurboHydramatic were no longer available in 1975. The 400 and 455 engines were optional above the base six and V8 in the 1975 and 1976 models.

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). 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. 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 Smokey and the Bandit II.

Source: Wikipedia, 2011

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