i haven't owned a 4cyl but i've driven them, and as previously stated they are worthless, if your going up a grade, don't even think about passing anyone, just put your foot in it and try to hold your speed. My dad has an 81 CJ8 with the 258 I6, which i beleive is the 4.2L, and that thing doesn't have a problem goin uphill with the 4spd, and always had power on the trail when it was needed. however, like aero mentioned earlier its a cj and it's on like its 5th clutch now i think, but then again, it's done a lot of trails, and my dad never upgraded the gears, so he had to use the clutch alot to control his speed.