I have a 1998 4.0 Cherokee that overheated and damaged no 1 piston. Cylinder is still good so I dodged a bullet there. I have a new early std piston and ring set with the thicker imperial sized rings. From memory Jeep changed over to the piston design with the "thinner" metric rings around 1996.

Can I use the early piston /ring in the 98 engine? Dimensionally they are the same as far as diameter and pin location. My query would be more about the early piston being differently weighted to the other five pistons or any other considerations people may know of.

Thanks for any feedback

Run it. I see no issue. You could weigh the replacement and compare to others. Your call.