The Iron Duke engine (also called 151, 2500, Pontiac 2.5, and Tech IV) is a 151 cu in (2.5 L) straight-4 piston engine built by the Pontiac Motor Division of General Motors from 1977 until 1993.

Nov 22, 2025 · Developed by GM’s Pontiac division and displacing a substantial 2.5 liters, this four-cylinder wonder proved to be a reliable and serviceable powerplant for many decades. In fact, GM …

The Iron Duke was a 4-cylinder, cast-iron pushrod engine born from oil shortages and government standards that demanded cleaner vehicles. The Iron Duke would see itself in a slew of GM vehicles …

Nov 18, 2025 · Iron Duke engines powered several AMC models between 1979 and 1983, including Spirit, Concord, 4WD Eagle, and Jeep CJ. The initial RWD configuration of early Iron Duke engines...

Sep 22, 2025 · Its architecture drew on Chevrolet’s legendary small-block V8. The bore and stroke measured out as if someone had sliced a 305 or 350 V8 in half, creating a straightforward four …

Oct 14, 2022 · In 1973, Pontiac started designing the Iron Duke engine with five basic goals in mind. They wanted to minimize noise and vibration (NVH), produce usable power at low engine speeds, …

The Iron Duke engine, also known as the Pontiac 151, is a 2.5-liter (151 cubic inch) inline-four gasoline piston engine with a cast-iron block and cylinder head, featuring an overhead valve pushrod valvetrain.

Aug 12, 2023 · The Iron Duke engine was introduced by General Motors in 1977 and was derived from the 2.2-liter four-cylinder Pontiac engine. Initially designed as a durable and fuel-efficient power …

Jun 8, 2022 · The GM Iron Duke is a 151ci inline four-cylinder gasoline engine. Produced under the Pontiac brand name between 1977 and 1993, the Iron Duke is prolific in small cars and utility vehicles.

Feb 10, 2024 · The Chevy 153 engine, also known as the “Iron Duke,” is a four-cylinder engine that was manufactured by General Motors from 1962 to 1979. It was primarily used in compact cars and light …