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
Rebuilding a 4.0L Jeep Straight Six to 242HP - Engine Power S2, E14 - YouTube
Jeep 4.0l 6 Cylinder Engine 00-04 78k Mile Wrangler Cherokee for sale online | eBay
R8272107AA 4.0L i6 Jeep Long Block - Mopar Powertrain