In 1957, Pontiac again increased the displacement of its V8 engines, to 347 cubic inches, For the first time, Pontiac offered what became their iconic intake option, three two-barrel carburetors. Pontiac called their set up “Tri-Power,” and was colloquially called “three deuces.” The Tri-Power option was available through the 1966 model year. In 1957, Pontiac also offered a mechanical fuel injection system on the new Bonneville model.

The base two-barrel 347 was rated at 227 HP; the four-barrel options were rated at 244, 252, and 270 HP. The two tri-power offerings were rated at 290 and 317 HP. The fuel injected engine was rated at 295 HP.

The pictured engine has had it’s original generator replaced with an alternator, and the chrome valve covers are probably not original to the engine.