Jeep 4.0 guys,check this out....

On their website they advertise gains of about 25 hp and 24-34 foot lbs over stock.
Jeep stock specs are 190 hp and 225 foot lbs of torque (235 lbs for 2001-2006 models)
Aluminum Cylinder Heads - Jeep 4.0l Inline Six - Performer - Edelbrock, LLC.