strech117

im looking to triple the lif of my xj, and my first step is to put in a rebuilt engine. with all the performance bells and whissles of course. i have a 91 and the easiest way for me to do this is to buy a beater engine, rebuild it, then swap it in so my jeep isnt down for more than a day or two
question is: what would be the best year or years to find to swap in easy? i figure another 91 HO would be ideal but that is pretty hard. i know that up to 96 alot stayed the same in the xj. is it a safe assumption that a 4.0l from a 96 would bolt right in easy to my 91?
im not so much thinking literal bolt points, but sensors etc.
any help would be awsome!

alloutperform

plug and play? 91-95.....96 is obd2...any long block 4.0 up til 98 (oil pan to valve cover) should work but you will need to swap sensors around after 95