The AMC 150 2.5L engine has a bore of 3.875 in and a stroke of 3.1875 in. The head features a combustion chamber and port design that was later used on the 4.0L — the 2.5L I-4 head gained two cylinders in its center for use the six-cylinder engines. The 2.5 engine also features five main bearings and eight overhead valves.