Built in large- in fact, vast- quantities from 1977 through 1993, the 151-cubic-inch Iron Duke four-cylinder served The General well, though generally without much recognition.
Known variously as the Iron Duke, Pontiac 2.5, and Tech IV, this pushrod four was an available powerplant in just about every car and small truck built by Pontiac, Chevrolet, Buick, and Oldsmobile during the Late Malaise Era and beyond. From the Camaro to the Fiero, S-10 to Skyhawk; even some late AMCs got Iron Duke power. The Duke tended to be on the noisy side and was often derided for its behind-the-times cast-iron construction and pushrod valvetrain, but it was compact and reliable- in many cases, the most reliable component in the car- and got the job done.
[Wikipedia]