2.5 L Iron Duke I4

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. Originally developed as Pontiac's new economy car engine, it was used in a wide variety of vehicles across GM's lineup in the 1980s as well as supplied to American Motors Corporation (AMC). The engine was engineered for fuel efficiency, smooth operation, and long life, not for performance. Total Duke engine production is estimated to be between 3.8 and 4.2 million units.