Your 2.5 is an AMC designed engine. First came out in 1984 as a "fuel feedback carb" version installed in the then new XJ Cherokee. Changed to fuel injection for 1986,used in the Cherokee ( rare) almost to the end. More common in the base model YJ and TJ Jeeps.
I owned (12 years) an 84 Cherokee with this engine. Not a lot of power in 84 but still a better engine than the GM 2.8 V6 also available.I had no problems with mine.
I wouldn't think you should have too much problems finding a good used engine. Any decent autowrecker will have "Hollander Interchange Manuals" which will tell you what year engine will fit and what if any changes you have to make. Just guessing I would think the basic engine would probably swap from 1987 or so on. You might have to swap some sensors/manifolds/external parts but Hollander will give you that information.
If you have any problems finding the interchange locally let me know and I'll call a wrecker here and see what they say.
