Dude if indeed you have a 94 Wrangler with the 2.5 you most likely have a 4:10 gear and that thing should hiway the same as all others like it. If you have oversize tires the hiway speed will decrease some for every size you go UP! So the best way to get back to normal is to go back to the correct size tire..
Taking that 2.5 fuelie out and installing ANOTHER engine can be a mess. If you go with another fuelie 4.0 you will have to replace wireing and computer and exhaust pipes, radiator, motor mounts, tranny, transfer case and driveshafts... just to get started! It will take months and months of your time and the Jeep will be on blocks all the while..
Are you ready for all this? I AM and I CAN! But I have a shop and plenty of spare time to do $hit like this. If YOU do not have the time, then trade that sucker in on an already six cylinder.. or change back in tire size!
Big JIm <img src="/forums/images/graemlins/pfft.gif" alt="" />