1970–1981 Pontiac Firebird/Trans Am (2nd Gen) Guide

1970–1981 Pontiac Firebird / Trans Am (2nd Gen): History, Specs, Variants, and Buying Advice

Historical Context and Development Background

The second-generation Pontiac Firebird bowed in early 1970, arriving as a lower, wider, and more aerodynamic evolution of GM’s F-body platform shared with the Chevrolet Camaro. While the car carried the name of the SCCA Trans-Am series, Pontiac’s factory racing presence was restrained by emissions, insurance, and corporate directives of the era. Nevertheless, the street-going Trans Am became a performance flagship for the division, with the base Firebird, luxury-leaning Esprit, and hot Formula completing a broad lineup through 1981.

Corporate Strategy and Platform

GM’s F-body employed a unitized shell with a bolt-on front subframe, short/long arm (SLA) front suspension, and a live rear axle on multi-leaf springs. Pontiac tuned its variants with distinctive powertrains and chassis calibration, culminating in the Trans Am. Throughout the decade, corporate horsepower retrenchment, unleaded fuel, and emissions controls redefined performance. Pontiac responded with larger displacement torque (455 HO, then the Super Duty), later pivoting to chassis sophistication via WS6, and finishing the era with a turbocharged 4.9L V8.

Design and Aerodynamics

The clean, semi-fastback profile of 1970–1973 (often called the “Endura-nose” or pre-facelift) emphasized coke-bottle flanks and a low cowl. For 1974, energy-absorbing bumpers reshaped the nose and tail; 1977’s update introduced quad rectangular headlamps and the iconic shaker hood scoop. Functional aero pieces evolved from subtle front air dams to deeper spoilers, extractor vents, wheel arch spats, and, on higher trims, a prominent rear spoiler. Graphics ranged from restrained scripts to the unmistakable “screaming chicken” hood decal that would become synonymous with the Trans Am.

Motorsport and Competitors

While not a factory Trans-Am contender, the model’s branding was apt: the early-’70s cars had the hardware—Ram Air induction, big-inch torque, quick steering—to excel in showroom stock and club-level competition. As the decade changed, rivals shifted: the Challenger/Cuda duo faded after 1974; Ford’s Mustang II reset the muscle car’s mission before the Fox-body era returned power; Z-car imports pushed reliability and balance; and the Camaro mirrored many Firebird mechanicals. The Trans Am’s enduring edge became its blend of torque, poise, and image.

Engines and Technical Specifications

Pontiac’s V8 family defined the 2nd-gen Firebird—particularly the 400 and 455. Through the era, horsepower ratings transitioned from SAE gross to net, and compression ratios fell to meet emissions and fuel realities. The high-water marks were the 1970 Ram Air packages, the 1971–1972 455 HO, and 1973–1974’s homologation-caliber 455 Super Duty. In the late ’70s, the W72 400 and WS6 chassis kept the car relevant; the final years adopted a turbocharged 301 cu in (4.9L) to chase performance within regulatory constraints.

Driving Experience and Handling Dynamics

Second-gen Firebirds deliver period-correct muscle balanced by surprising chassis competency. Steering is a fast-ratio, recirculating-ball setup with decent on-center and ample assist, especially on WS6 cars. Early cars feel raw—big-cube torque, shorter gearing, and heavy controls—while late-’70s examples, particularly W72/WS6, emphasize grip and composure over outright thrust.

Suspension Tuning

All models share SLA front suspension and a live axle on leaf springs. The WS6 package (introduced for 1978) upgraded spring and bushing rates, added larger anti-roll bars, quick-ratio steering, specific shocks, 15×8 cast-aluminum “snowflake” wheels, and stickier tires; from 1979, 4-wheel disc brakes were available with WS6. The result is flatter cornering, better transient response, and a far more contemporary feel than its spec sheet suggests.

Gearboxes and Throttle Response

Manuals were Muncie 4-speeds in the early years, later Borg-Warner Super T-10s; automatics were 3-speed Turbo-Hydramatics (TH400 behind early high-torque engines, TH350 elsewhere). W72 cars respond crisply with a properly tuned Quadrajet, while the 4.9 Turbo delivers midrange boost with a distinct surge once on-song. Carburetion and ignition state of tune have an outsized effect on drivability; a healthy, tight chassis makes these cars feel smaller and more precise than their footprints imply.

Performance Specifications (Representative)

Figures reflect period testing and typical gearing/trim; individual results vary by equipment, altitude, and test methodology.

Variant Breakdown

Core Trims

Trans Am Yearly Production (Select)

Special Editions and Limited Runs

• 1973–1974 Trans Am 455 Super Duty: 252 (1973 TA) and 943 (1974 TA) built; reinforced blocks, unique internals, and underrated performance.
• 1976 Trans Am 50th Anniversary SE (black/gold): approximately 2,590 produced; distinctive black paint, gold pinstriping, and special wheels.
• 1978 Y88 Gold Special Edition: approximately 8,666 built; gold paint, gold “snowflake” wheels, gold-accent interior trim.
• 1979 10th Anniversary Trans Am (silver/charcoal): 7,500 built; unique silver leather, special decals, and available 4-wheel disc WS6.
• 1980 Trans Am Indy Pace Car (Turbo 4.9): approximately 5,700 built; white/charcoal with pace car graphics and specific interior details.

Ownership Notes: Maintenance, Parts, and Restoration

What to Inspect

• Rust hot spots: lower fenders, rocker panels, rear quarters, trunk drop-offs, floor pans, cowl/firewall seams, subframe mounts, and rear window channels. T-top cars deserve close scrutiny around the roof structure and sail panels.
• Chassis: subframe bushings, leaf spring pads, and steering box play. WS6 cars should wear proper 15×8 wheels and the correct rear disc hardware (1979 availability).
• Powertrains:
  • Pontiac 400/455: cam and lifter wear if run on low-zinc oils; verify oil pressure hot; check for timing set wear and vacuum integrity.
  • 455 SD: confirm numbers-matching block and heads; internal SD-specific parts are costly and specialized.
  • 4.9 Turbo: ensure wastegate and boost controls function; detonation from vacuum/ignition issues can be terminal on a marginal engine.
  • Quadrajet: proper calibration is key; many driveability problems trace to vacuum leaks or misadjusted chokes rather than the carb itself.

Service Intervals and Running Costs

• Oil and filter: ~3,000–5,000 miles depending on use; flat-tappet cams benefit from high-zinc formulations.
• Ignition: cap/rotor/plugs every ~12,000–15,000 miles; verify base timing and vacuum advance.
• Cooling system: pressure test; flush every ~2 years; watch for clogged radiators on big-cube cars and 4.9 Turbo heat management.
• Driveline: differential fluid ~30,000–50,000 miles; gearbox/automatic service on schedule to preserve shift quality.
• Brakes: rear drum adjusters and parking brake linkages tend to seize if neglected; 1979 4W-disc hardware is model-specific.

Parts Availability and Restoration Difficulty

Mechanical parts are broadly supported, with strong specialist networks for Pontiac V8s and F-body chassis. Sheet metal, interior plastics, and correct-appearing trim are available but quality varies; original GM pieces command premiums. Restoring an SD-455 or rare SE to factory-correct specification is detail-intensive due to exclusive components, finishes, and documentation requirements.

Cultural Relevance and Market Perspective

The second-gen Firebird transcended spec sheets. The Esprit became a small-screen staple, while the black-and-gold Trans Am etched itself into film history, catalyzing late-’70s sales. Among enthusiasts, the 1973–1974 SD-455 sits at the apex for performance and scarcity, followed by early Ram Air and 455 HO cars, then well-documented W72/WS6 4-speed examples. Special Editions—1976 50th, 1978 Y88, 1979 10th Anniversary, and 1980 Pace Car—have enduring appeal. Auction and private sales have repeatedly shown six-figure results for top SD-455 cars, with strong, rising interest in highly original, low-mile W72/WS6 cars and correctly optioned SEs.

FAQs

Which 2nd-gen Trans Am is the quickest from the factory?

In period testing, the 1973–1974 455 Super Duty cars posted the strongest numbers, with ~6-second 0–60 mph and low-14-second quarter-miles when properly tuned. Early 1970 Ram Air IV cars are also very quick and highly prized.

What’s the difference between WS6 and W72?

W72 is the late-’70s performance 400 V8 package (200–220 hp net). WS6 is the handling package introduced in 1978, adding stiffer suspension, bigger anti-roll bars, 15×8 wheels/tires, quick steering, and from 1979, available 4-wheel discs.

How can I verify a real SD-455?

Check the VIN, engine block and head casting numbers, and the presence of SD-specific features (reinforced block, unique cam/rods, emissions decals). Documentation (build sheet, PHS records) is essential.

Are 4.9 Turbo cars reliable?

Stock, well-maintained examples are serviceable. They demand correct ignition timing, functioning boost controls, and healthy cooling. Detonation from vacuum or control issues is the primary risk; modifications should be conservative.

Where do these cars rust first?

Rear quarters, trunk drop-offs, lower fenders, floor pans, cowl, subframe mounts, and rear window channels. T-top roof structures need careful inspection.

What are value drivers?

Originality, documentation, drivetrain (SD-455, Ram Air, 455 HO, W72), gearbox (4-speed desirability), WS6, special editions, colors/graphics, and low mileage. Correct parts and finishes significantly influence top-tier results.

What engines were offered across the range?

From 1970–1981: Chevy-sourced 250 I6 (early), Buick 231 V6 (late), Pontiac 350/400/455 V8s (varying outputs), the high-spec 455 HO and 455 SD, the W72 400, and the Turbo 4.9 (301) in 1980–1981.