Pontiac stopped offering the 455 engine in 1976, meaning this 1978 Trans Am’s big-inch V8 isn’t a factory original, it’s the car’s numbers-matching 400 block, bored and stroked to 455 cubic inches during a full restoration. Edelbrock heads, a roller cam, and a rebuilt Quadrajet back up the added displacement. The result blends genuine muscle-era hardware with modern conveniences like Bluetooth audio.