The "350HP" is the next step up the ladder to more performance out of your 4.0 based Jeep/AMC motor. This combo features a more aggressive cam profile to give that "Lopey/Rowdy" idle
A Tribute to the “Straight Six”: Jeep's Legendary 4.0L
Jeep Engine Parts Diagram - OEM Replacement 4.0 Liter (242) AMC Engine TJ, YJ, XJ, ZJ, WJ & Grand Wagoneer Diagram - Morris 4x4 Center