Can I replace an 02 Engine with an 07 engine?
Does the engine need to have the same 8th digit/letter as the original did?
Just want my kids car fixed so I can have my car back.

 

While I do not know the direct answer to your question, be sure to research thoroughly before moving forward. I know for a fact to LH series cars have some quirks. Example 99-01 need to swap Flywheels and cam drives to work in 02-04.
Around 2004-5 Chrysler significantly changed computer control systems making pre and post incompatible with out mechanical changes also needed.

Good luck.
https://www.chryslerforum.com/forum/...ne-swap-34024/
https://www.chryslerforum.com/forum/...ne-swap-34240/

 

There was a significant change in the electronic engine control system halfway through the 2004 model year. If you know exactly what you're doing you might be able to make that swap work. If you're looking for a plug-and-play swap, get an engine from the same model year.