aclayton1

hi. am new member. i have an 87 cherokee, laredo 2 wheel dr.it has a 4.0 that is bout ready to be retired.i have another 4.0 out of a 98 cherokee. have gotten conflickting info. is it going to hook in with the current harness.or will i need a new computer and all

98jeepsrt6

If your 89 has a renix, which its should. you would need new harness and all to put the H.O in.

Jamie57

NO NO NO NO!!!!!
If he just puts in the long block and uses his existing intake and exhaust and power steering pump etc why does he need the wiring harness?
He can even use the 89 distributer. Again no need for more wiring.
HOWEVER if he wants to update the computer etc. then yes he needs the harness and a lot of Tylenol for the headaches he's going to have trying to make it work.
Why do you guys keep giving out bad info to the new guys!

There may be a problem with a temp sensor at the back of the 89's head. The newer heads do not use it and don't have a hole for it. You can drill the head and tap it yourself if you desire to see it on your guages.
That's about the only problem he should have.

98jeepsrt6

Didnt give him bad info.. he asked a question without stating his main purpose. He didnt ask if he should tear down and swap parts.. He ask a direct question and i gave the direct answer.. the op has been in the middle of conflicting responses before so i figure give it to him straight.

But yes, with the above statement is very true.. all depends on what the op has time for or whether or not he wants to upgrade to fuel injected over carburated.

cruiser54

It's already fuel injected.

I've done cross-year swaps 3 times, substituting later model HO engines where a Renix era engine was. If the donor engine has no provision for the temp sender in the head, use it's threaded hole in the thermostat housing to mount the sender there. Be sure to remove a block plug from the driver side of the donor engine for your Coolant Temp Sensor. Use your distributor and flexplate/flywheel along with intake and exhaust manifolds. Any questions post 'em up.

aclayton1

thanks. evryone. didnt mean to confuse.i will probably have more questions. was planning on using all components fron the 98 engine. i may have to rethink my plans based on your recomendations