GM Iron Duke engine

The Iron Duke (also called the 2500, 151, Pontiac 2.5, Cross Flow, and Tech IV, though the decal on the air filter assemblies actually reads "4 Tech") was a 2.5 L (151 in³) I4 piston engine. All Iron Dukes were built by Pontiac beginning in 1977 and ending in 1993.

This 151 was also used by American Motors (AMC) starting in 1980, as the base engine option in the RWD Spirit and Concord, and continuing in both cars through 1982. The AWD (4x4) Eagle carried the 151 as standard equipment for 1981, and carried it midway through the 1983 model year. It was also available (as the Hurricane) in economy model Jeep CJs. AMC replaced the Iron Duke 2.5L I4 with a 150cid Inline-4 of their own, derived from their evergreen sixes.

The Iron Duke is often confused with Chevrolet's Stovebolt-derived 153 from the 1960s Chevy II, but the engines are entirely different - the Iron Duke's intake manifold is on the passenger side, as opposed to the driver side. One thing that both share is the Chevrolet Small-Block bell housing bolt pattern.

Applications:

* 1977 Pontiac Astre
* 1978-1980 Pontiac Sunbird
* 1984-1988 Pontiac Fiero
* 1982-1985 Chevrolet Camaro
* 1985-1990 Chevrolet Astro
* 1985-1990 GMC Safari
* Chevrolet Celebrity
* Chevrolet S-10
* Chevrolet S-10 Blazer
* GMC Sonoma
* GMC S-15 Jimmy
* Chevrolet Monza
* Buick Skylark
* Buick Skyhawk
* Buick Century
* Pontiac 6000
* 1985-1991 Pontiac Grand Am
* Oldsmobile Ciera
* Oldsmobile Omega
* AMC Concord/Spirit (1980-82)
* Eagle (1981-83)
* Jeep CJ (1980-83)
* Grumman LLV United States Postal Service delivery vehicle