What kind of engine should I put in to get better gas mileage?

same thing that came in it,being 4x4 and a big vehicle,not much will help on gas milage.

thanks! that sucks. I get about 15 miles per gallon. Not so good. But it's such an awesome vehicle, I don't want to part with it. I'm ready to put some work into it. How would a diesel do? Then I could convert it to bio-diesel....

that would be very costley and hard to do.

The most effective way I know of to drastically improve gas mileage would be to change the gear ratios in the axles. For example, go from 4.10 gears to 3.73 gears. However, this will make your vehicle accelerate slower and have a more difficult time under heavy loads and going up hills.

who are you,your post dont make since.your advice would make it worse,and in another post you say 12.6 volt is a good alt.get it right or go away.

3.73 means that the driveshaft turns 3.73 times for every time the wheels turn, 4.10 means it turns 4.10 times for every time the wheels turn. Engine does more with every degree of rotation. 12.6 volts is the minimum to turn the starter, where did you go to school?

I know what all that means,learn,anything under 14 volts is to low,12.6 wont start a riding lawn mower,dont matter where i went to school,it is where i learned to be a REAL MECHANIC,so how about stoping stupid post and learn the mechanics of vehicles.