Upon adding 33-inch-tall tires, a flexy long-arm suspension system, and enough camping essentials to forget home while on the trail, our donor's '05 Jeep Rubicon Unlimited felt a bit on the sluggish ...

The 4.0-liter straight-six made famous for its use in Jeeps in the Eighties and Nineties is known for many things, but power isn't one of them. It's a workhorse motor, meant to take abuse and run ...

Jeep’s 4.0-liter straight-six engine is iconic. Much like the Ford 300, it’s a down-and-dirty truck engine that stayed in production for decades. Also like the Ford 300, it can make a ton of power ...