New Guy With 4.0 Question

[Brbrooks83]

I am buying a 1988 comanche it's a 2.5 4 banger. How hard would it be to put a 4.0 in it??

[Jeep Driver]

I'd buy a complete 88 donor...........that runs.

[onlyinajeep726]

http://comancheclub.com/topic/39539-links-for-25l-to-40l-swap/
 
My suggestion, find you a good donor to pull everything from.  This will help out tremendously.  Not only will you have everything you need, but you can see the placement of all the individual pieces so you can get them back together in you MJ.  Also, do LOTS of research before you get wrenching.  You'll be glad you did.

I'd buy a complete 88 donor...........that runs.

The only thing I'd change about this suggestion is the year. Technically, you can use anything '87 - '90, but I'd recommend a late '89 or '90 to avoid the dreaded C101 connector.  That's IF you want to keep it Renix.  You can find yourself an HO ('91+) and use the Chrysler management system (OBD I).  It's about what you want to do and how deep your pockets are.