Pontiac marked the Bicentennial with the last of the true muscle cars -- complete with a 455-cubic-inch engine
The American Bicentennial was a great year for the country, but a dismal one for performance cars. Passage in 1970 of the federal Clean Air Act and the industry-wide adoption of catalytic converters beginning with the 1975 model year had ended the reign of big-engined muscle cars as effectively as the asteroid that killed off the dinosaurs.
But Pontiac was at least trying. GM's "performance division" - which arguably kicked off the whole muscle-car fandango with the launch in 1964 of the first GTO - hadn't totally given up on performance. The real thing, too, not just decals and a faux muscle car strut.
The '76 Trans Am 455 four-speed was clear proof of that. Someone still gave a damn about cars with a pulse. Granted, its 200 horsepower was nothing special compared with the Super Duty, Ram Air, and High Output 400s and 455s that preceded it. But it had one critical thing going for it that few other engines or cars still had that Bicentennial year: It was B-I-G, all 455 cubic inches' worth.
By 1976, the biggest engine you could get in a Camaro was a small-block 350. The Mustang II was just pathetic. No more 'Cudas; no more 383 Super Bees. Just a depressing vista of rich, Corinthian leather, fake wood paneling, and sill stripe and decal jobs.
Only Pontiac still offered a legit player. And the huge engine in the Trans Am didn't have any unique high-performance parts, not even a low-restriction air cleaner. It was, in fact, identical to the low-rpm boilerplate 455s used to lug around Catalina station wagons, with 7.6:1 compression, small valve heads, and a powerband that ran out of steam at 4500 rpm.
But what made the whole thing special was the package that Pontiac made of it and all the potential locked up inside it. First, it wasn't just an engine. When you ordered the code L75 455 (in place of the standard 185-hp L78 400 V-8), you also got a much more aggressive 3.23 ratio Positraction-equipped rear axle (in place of the standard 2.41), uprated brakes (with sintered metallic shoes/pads lifted from Pontiac's police-duty equipment package) and a lower-back pressure transverse-mounted muffler ending in twin chrome "splitter" tips. You also got the famously fun M-21 close-ratio four-speed manual transmission with Hurst shifter (if you wanted an automatic, you wanted another car). Stock, the combo was good for mid-high 15-second quarter mile times and 0-60 clockings in the seven-second range - excellent performance in an otherwise bleak landscape for the enthusiast car buyer.
Fiddling with the Rochester Quadrajet four-barrel carburetor (which was set lean for emissions reasons), dialing up a more aggressive spark curve and ditching the stock single-cat exhaust system in favor of headers and dual exhaust would make the car downright respectable. In 1976, you ruled the roost if your car had those bad-boy "455" call-outs on its shaker scoop - especially if you'd removed the government-required block-off plate to let gobs of fresh air feed the mighty engine unrestricted.
Trans Ams in general got a huge boost around this time as well from the now-iconic Burt Reynolds/Sally Fields burnout-fest, Smokey and the Bandit, which starred a black-and-gold Trans Am laying rubber and flummoxing cops in a dozen counties. Originally, the movie was to have featured a '76 Trans Am, which was the debut year for the menacing black-and-gold paint scheme, based on the John Player race cars of the time. It was a striking car, with German-style lettering for the engine callouts on the shaker scoop and "Trans Am" on the fenders providing the finish touches of malevolence. Standard equipment in these cars, which were technically 50th Anniversary Limited edition models, was the L-78 400 V-8. But the Mack Daddy 455 was the hot ticket option. T-tops (designed by Hurst) appeared this year as well and first became available in these '76 LE anniversary cars.
However, production delays resulted in the movie being shot with a '77 model - and by then, major changes had taken place. The 455 was gone, replaced by a new "T/A 6.6-liter" 400 that offered about the same horsepower but nowhere near the street cred of the big bruiser. (Many scenes in the movie were done with a 455-equipped car that had been modified to "bark the tires" on a hard one-two upshift in a way the standard car just couldn't manage.) The '77s also marked the debut of a significant body restyle that included a new quad-headlight front end, flat hood, and smaller, less belligerent-looking hood scoop.
The bicentennial year was the last hurrah, and not just for the 455. Also gone were the unusual "polycast" 15x7 honeycomb wheels that had first appeared in 1971. These looked like alloys but were in fact steel with a flexible urethane composite material injection-molded to the rim to give the appearance of an alloy, albeit with the strength of steel. Unfortunately, the polycast rims were also heavy; they were dropped in favor of aluminum "snowflake" wheels for 1977, making '76 the last year for these. The shovel-nose, single-headlight front-end treatment was retired, too, and wild colors like Carousel Red (identical to the hue used on the '69 GTO Judge) and Goldenrod Yellow were discontinued.
But the absence of the option-code L75 455 V-8 was most the most obvious change. It marked the turning of the final page of the final chapter of the original muscle-car era. Never again would an American automaker offer such an enormous engine in a compact-sized car.
It shall not pass this way again.