i wanna know more bout slant sixes

my jeep has a 4.2 inline six i put it in there but yea i get about 13 mpgs my jeeps a 89 wrangler i love it robs right it makes great torque i think the peak is like 1600 rpms its great for rock crawlin you just gotta gear it i just wont be able to drive it during college itll eat me alive on gas so i figured since im a big fan of dusters maybe id get one with the slant for my everyday driver that gets good gas milage then still have the jeep who knows after college i may put a 5.7 or 6.1 hemi in the duster but for now im mainly explorin my options and i aint gunna rush i got another year till its a big issue n i want to get as good a deal as i can find plus im broke lol so power is probly gunna be an issue hope its got more than a 99 stratus 2.4 liter auto ah well thats not what they are for i guess