How hard is it to replace lifters on a 4.0 inline 6 88 Cherokee,I have never done something like this before but I wanna learn

 

Dustin, why do you think they need replacing? If you're getting the "lifter click" it may be the rocker arm bridges. Not sure about the 4.0 but i've had to change a few sets on 258's.
Not a 100% sure on this but IIRC, to change the lifters, the head has to come off.