The first generation Firebirds had a characteristic Coke bottle styling. Unlike its cousin the Chevrolet Camaro, the Firebird's bumpers were integrated into the design of the front end. The Firebird's 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 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 (190 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).
Source: Wikipedia (original)