If the engine is siezed, most likely its done, and cant be repaired short of a rebuild. 6G72 is a very common engine. Found in Quite a few dodge and Crysler Minivans, lebarons etc. You could probably find a good bottom end out of one of those..Make sure you keep the Montero engine around to swap all the needed parts over. Also the dipstick is on the wrong side in the Crysler applications so to ease the swap you might want to get it out of another Montero or Mighty max truck..this engine was also in the Mitsu Diamante among others..do some research and look around.