The first generation Firebirds had a characteristic Coke bottle styling. Unlike its cousin, the Chevrolet Camaro, its bumpers were integrated into the design of the front end and its rear "slit" taillights were inspired by the Pontiac GTO. Both a two-door hardtop and a convertible were offered through the 1969 model year. Originally the car was a "consolation prize" for Pontiac, who had initially wished to produce a two-seat sports car of its own design, based on the original Banshee concept car. However, GM feared such a vehicle would directly compete with Chevrolet's Corvette, and the decision was made to give Pontiac a piece of the pony car market by having them share the F-body platform with Chevrolet.
The base model Firebird came equipped with the OHC inline-6 and a single-barrel carburetor. The next model, the Sprint, had a four-barrel carburetor, developing 215 hp (160 kW). Most buyers opted for one of the V8 engines: the 326 CID (5.3 L) with a two-barrel carburetor producing 250 hp (186 kW); the "H.O." (High Output) engine of the same displacement, but with a four-barrel carburetor and producing 285 hp (213 kW); or the 400 CID (6.6 L) from the GTO with 325 hp (242 kW).
A "Ram Air" option was also available in 1968, providing functional hood scoops, higher flow heads with stronger valve springs, and a different camshaft. Power for the Ram Air package was the same as the conventional 400 H.O., but the engine peaked at a higher RPM. The 230 CID (3.8 L) engines were subsequently replaced by 250 CID (4.1 L) ones, the first developing 175 hp (130 kW) using a single-barrel carburetor, and the other 215 hp (160 kW) with a four-barrel carburetor. Also for the 1968 model, the 326 CID (5.3 L) engine was replaced by one with a displacement of 350 CID (5.7 L). An "H.O." version of the 350 CID with a revised cam was also offered starting in that year, developed 320 hp (240 kW). Power output of the other engines was increased marginally.
In 1969, a $725 optional handling package called the "Trans Am Performance and Appearance Package,", named after the Trans Am Series, which included a rear spoiler, was introduced. Of these first "Trans Ams," only 689 hardtops and eight convertibles were made. There was an additional Ram Air IV option for the 400 CID engine during that year, complementing the Ram Air III; these generated 345 and 335 hp (250 kW) respectively. The 350 "H.O." engine was revised again with a different cam and cylinder heads resulting in 330 hp (250 kW). During 1969 a special 303 cu in (5.0 L) engine was designed for SCCA road racing applications that was not available in production cars.
The styling difference from the 1967 to the 1968 model was the addition of Federally mandated side marker lights: for the front of the car, the turn signals were made larger and extended to wrap around the front edges of the car, and on the rear, the Pontiac (V-shaped) Arrowhead logo was added to each side. The front door vent-windows were replaced with a single pane of glass. The 1969 model received a major facelift with a new front end design but unlike it's big brother the GTO, it did not have the Endura bumper. The instrument panel and steering wheel were revised. The ignition switch was moved from the dashboard to the steering column with the introduction of GM's new locking ignition switch/steering wheel.
Due to engineering problems that delayed the introduction of the all-new 1970 Firebird beyond the usual fall debut, Pontiac continued production of 1969 model Firebirds into the early months of the 1970 model year (the other 1970 Pontiac models had been introduced on September 18, 1969). By late spring of 1969, Pontiac had deleted all model-year references on Firebird literature and promotional materials, anticipating the extended production run of the then-current 1969 models.
Source: Wikipedia, 2013