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The second generation debut for the 1970 model year was delayed until February 26, 1970, because of tooling and engineering problems; thus, its popular designation as a 1970½ model, while leftover 1969s were listed in early Pontiac literature without a model-year identification

Special versions

Black Special Edition (often called ‘Bandit’ editions)
Gold Special Edition
Macho Trans-Am (Package offered only by the dealership Mecham Pontiac in Glendale, AZ).[6]
1976 50th (Pontiac) Anniversary Edition
1979 10th (Trans Am) Anniversary Edition
1980 Pace Car Indy 500 Edition (turbo Trans Am)
1981 NASCAR Edition (turbo Trans Am).[7]
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 1973 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 (1973 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.[8]

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.

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 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.

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.

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 Smokey and the Bandit II.

Trans Am hood, 1978
Beginning in 1978, Pontiac engineers reversed years of declining power by raising the compression ratio in the Pontiac 400 through the installation of different cylinder heads with smaller combustion chambers (1977 Pontiac 400 engines also had the 350 heads bolted to the 400 blocks, these heads were known as the 6x-4 heads) (taken from the Pontiac 350). This increased power by 10% for a total of 220 during the 1978–79 model years. The 400/403 options remained available until 1979, when the 400 CID engines were only available in the 4-speed transmission Trans Ams and Formulas (the engines had actually been stockpiled from 1978, when PMD had cut production of the engine). 1979 marked the 10th Anniversary of the Trans Am, and a special anniversary package was made available: silver paint lower paint (with gray upper paint accents) with a silver leather interior. The 10th Anniversary cars also featured a special Firebird hood decal, which extended off of the hood and onto the front fenders. Pontiac produced 7,500 10th Anniversary cars, of which 1,817 were equipped with the Pontiac 400 engine (and coupled with the 4 speed Borg Warner Super T-10 transmission). The only option on these cars was the engine (the 400 was not certified for California, nor was cruise control available with it), which dictated the transmission and the gear ratio (3.23 on the 400 cars, 2.73 on the 403 cars). In 1979 Pontiac sold 116,535 Trans Ams which still holds the record to this day.

Up until the 1979 models, the performance of 400-equipped Firebirds could still be brought up to pre-1970 levels by disabling emissions equipment- removing the catalytic converter and blocking off the exhaust gas recirculation system- and opening up the block off plate to make the hood scoop functional. However, in 1980, due to ever-increasing emissions restrictions, Pontiac dropped all of its large displacement engines.[10]

1980 therefore saw the biggest engine changes for the Trans Am. The 301, offered in 1979 as a credit option, was now the standard engine. Options included a turbocharged 301 or the Chevrolet 305 small block.

In the final year of the Second Generation Firebirds (1981), Trans Am still used the same engines as it had in the previous model year, with the only change being the addition of a new electronic carburetion system.

 

 

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