The glorious blaze of the muscle car started to fade pretty quickly in the early Seventies. One of the remaining flames in the gathering darkness was the Pontiac Firebird. The senior F-body raged against the dying of the light for as long as it could, using Pontiac’s formidable 455-cu.in. V-8. When it debuted in 1970, the 455 was perhaps the ultimate refinement of Pontiac’s original 287-cu.in. Strato-Streak design of the mid-’50s.
The 455 hung on through 1976, although it was steadily detuned from its debut at 370 (gross, but probably understated) horsepower at 4,600 rpm and 10.25:1 compression. Of course, 1970 is generally recognized as the pinnacle of power output in the muscle era, but while most automakers simply began to detune their performance engines with lower compression and milder camshaft profiles, Pontiac wasn’t willing to throw in the towel just yet.
The result was 1971’s 455 H.O. engine, a package engineered to maintain respectable horsepower output paired with substantial torque, while also utilizing a low compression ratio—8.4:1 to be precise. The ’71 455 H.O. featured Pontiac’s “round-port” cylinder heads, a term that refers to the shape of the exhaust ports. This design had previously been featured on some of Pontiac’s highest-performing engines, including the Ram Air II and Ram Air IV 400s. The performance-tuned 455 for 1970 was also referred to as an “H.O.” but it had used Pontiac’s standard D-port heads. The new-for-’71 round-port 455 H.O. also featured Pontiac’s high-flow exhaust manifolds and an aluminum intake
Firebird buyers could have also selected a lower-output 455 D-port engine during the 1971 season, but when the ’72 models came out, the only 455 offered in the Firebird was the H.O., which carried a new net rating of 300 horsepower at 4,000 rpm. Torque was down only slightly, however, from the 500 lb-ft at 3,100 rpm of the high-compression era to a still-respectable 415-lb-ft at 3,200 rpm.
The flip side of lowered compression ratios (and other de-smogging and fuel-efficiency efforts) was that in order to sell performance cars with increasingly less sheer power, the manufacturers that wanted to stay in the game had to focus on two things: style and handling. A certain subset of period cars took the stylistic excesses to a questionable extreme, but once again Pontiac excelled, pushing out its Firebird pony car in various degrees of economy, luxury, and performance—all very easy on the eyes.
The second prong of the period performance strategy was competent manners in more than just a straight line. The 1964 GTO has been justly criticized for its handling and undersized drum brakes. By 1972, thanks to several years of research in the SCCA’s competition laboratories (i.e., Trans-Am racing), the Wide Track gene had reasserted itself in time to save the excitement in the Firebird line
At the top of the performance heap was the appropriately named Trans Am, with its shaker hood scoop, spoilers, and race-car vibe. For those with a more buttoned-down taste, the Trans Am’s capabilities could be had in Formula trim.
The Formula sat just below the Trans Am in the Firebird hierarchy. At the bottom was the basic Firebird, a no-frills car that came standard with a 250-cu.in. six-cylinder and a column-shifted three-speed manual transmission. The step up from that was the Esprit, which offered essentially the same car with some upgrades, like extra sound deadening, deluxe interior appointments, and V-8 power: a two-barrel, single-exhaust, 350-cu.in. V-8 with 8.0:1 compression. To that, the Formula added a 1-1/8-inch front anti-sway bar, firmer shock absorbers, fatter tires (still on 14-inch wheels) and some distinctive visual features.
A Formula didn’t come standard with all the Trans Am goodies, for sure, but most were on the option list. The X-code 455 itself, for example, was the standard engine in the $4,300-ish T/A, but despite the Formula’s exotic, fiberglass, dual-snorkel hood, a dual-exhaust, 175-hp version of the Esprit’s standard engine was the Formula’s base mill. A four-barrel, 400-cu.in., 300-hp engine was a Formula-specific option as well, for those who perhaps didn’t have the financial wherewithal to purchase and insure a 455