Pontiac 428 V8 Engine

The Pontiac 428 was introduced at the same time as the Pontiac 400 V8 in 1967 and used primarily in the Grand Prix, but also for the legendary GTO and Firebird models.

Although the 428 was modeled after the Pontiac 421, it had a cast iron crankshaft rather than the steel used in the 421. The 428 was one of the “long journal” V8 engines that Pontiac produced.

Because the 428 was used only in large cars like the GTO and Firebird and featured prominently in NASCAR stock cars, it was quickly replaced by the Pontiac 455 in 1970. The higher output 428 engines featured 1.91 inch valves and a 1.66 inch exhaust.

Engine Specifications

1967-1969 with 4-Barrel Carb

Max Brake Horsepower: 260@ 4600rpm (factory modifications increased hp to 270 in some models)
Max Torque: 472 @ 3200 rpm
Stroke: 4.0
Bore: 4.12
Compression: 10.5
Firing Order: 18436572

1967-1969 High Output with 4-Barrel Carb

Max Brake Horsepower: 360@ 4600rpm
Max Torque: 472 @ 3200 rpm
Stroke: 4.0
Bore: 4.12
Compression: 10.0
Firing Order: 18436572
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