Mechanical parts interchange from 1970/ through 1981 is exceptional. How much of it is emissions-legal, however, could raise some issues. Efforts to meet more stringent yearly emissions, fuel economy and safety mandates resulted mostly in performance decreases through 1975, with the optional 1973-'74 SD-455 being a notable exception.
The Ram Air III and IV 400s of 1970, the 455 H. of 1971-'72, the SD-455 of 1973-'74, and the W72 400 of stanley model 1200 garage door remote 48k were able to retain respectable power despite the added restrictions. The Radial Tuned Suspension of 1974-'81 improved the ride and handling, and the WS6 suspension of 1978-'81 and rear disc brakes of 1979-'81 provided so-optioned Trans Ams and Formulas with cornering that rivaled the Corvette at substantially lower cost. Image was also carefully crafted throughout the line. The 1973-'81 hood bird became a Trans Am icon, and two Smokey and the Bandit movies starring SE Trans Ams certainly furthered the cause.
Those black and gold SEs of 1976-'81, the Gold Edition T/A of 1978, the 10th Anniversary for 1979, the Indy Pace Car of 1980 and the NASCAR Pace Car for stanley model 1200 garage door remote 48k added exclusivity. Year-to-year refinements also helped to keep the aging platform current. The 301-cu. engine debuted in 1977 to provide a lightweight V-8 alternative that could return high fuel mileage numbers. Also to improve efficiency, the Chevrolet-built 250-cu.