The Edelbrock #50169 Performer Cylinder Head is designed as a bolt-on performance upgrade for 1987-2006 Jeep's with a 4.0L inline six engine. They feature better flowing intake/exhaust ports along with a modern combustion chamber design and back cut and swirl polished valves for improved flow. Retains the stock valve angle, pushrod length and valve cover bolt pattern for use with factory components and off the shelf accessories. Larger reinforced rocker bosses for improved strength at high RPM and Heli-Coil threaded inserts in the intake manifold bolt holes for added strength as well as a 3/4" deck throughout the head also promotes stiffness and durability. This cylinder head is machined to accept both distributor or coil pack ignition.