If you own a Jeep with a 4.0L engine, chances are pretty good that you either have, or will have, a cracked exhaust manifold. Oft-cited causes range from bad motor mounts to poor factoryprocesses.

Most likely, it was some GI during World War II that first started modifying Jeeps to better suit his needs. While there were many modifications made to meet certain war-time criteria, not much was ...