I want to put the motor from a 97 or 98 grand cherokee into a 94 the has a piston issue can this be done please say yes

If you mean the monster 4 litre petrol engine then yes because i have changed one as they are all the same block but you will ahve to sort the later to earlier ignition system but not a problem but use the parts off the old one,fitted a diesel into one as well for a car dealer as the petrol ones here are worthless pieces of junk,but a diesel with a manual box ?? around 5000 euros but a petrol with no LPG gas conversion even in good condition you might be lucky to get 500 euros ,scrap man will give you 50/100 euros .Highest value vehicles here when old are merc diesels or a peugeot /citreon/renault diesel cars ,petrol you cannot give them away least off all a 4litre gas guzzler with a auto box