1988 Jeep Cherokee carb intake vs fuel inject

Engine Mechanical problem
1988 Jeep Cherokee 6 cyl Four Wheel Drive Automatic 165k miles

Q.~How hard is it to change over the intakes from carb to fuel inject w/all else being the same.I have an' 88 w/258 inline 6cyl.~Found a motor which same, but has carb.--Want to use the carb motor, but need to switch it to fuel inject.