I just got a 5.2L ZJ today that needs an engine. Just wondering if the ECU is the only thing that needs to be changed if I were to put in a 5.9? Thanks

yup thats about it, actually your PCM will prolly work in the 5.9 as well, but you won't get the full power potential of the 5.9L, because the 5.9Limited's timing has been advanced 15 degrees which is where the extra power of the 5.9Limited comes in over other 5.9L vehicles (Dodge Rams, Durango, etc...)

Found me a motor in a 2000 Durango 5.9 this afternoon. Im going to get the motor mounts to make sure they are correct. Ill use the same PCM until I can get a 98 5.9 limited.