• Welcome to the new NAXJA Forum! If your password does not work, please use "Forgot your password?" link on the log-in page. Please feel free to reach out to [email protected] if we can provide any assistance.

Seeking info on possible swaps


NAXJA Forum User
North Carolina
Hey all, been a long while. Title pretty much sums it up, I recently was gifted an 04 KJ (3.7 v6) that the previous owner ran too hot. I'm curious if anyone has any info on possible engine swaps? I'm not a huge enough fan of the 3.7 & the body needs a lil more love than I care to wanna rebuild it but if I can slap a different engine in than I might seriously consider it.
You can swap in another 3.7 easily enough up to 2012 production, just make sure the reluctors are correct

Another engine like a v8 is another can of worms. It can be done but is a huge project. The pcm and body computers don’t play nice with other engines than what was equipped.

Sent from my iPhone using Tapatalk Pro
KJs 3.7 engines go like this
2002-2004 have a certain pcm and reluctor (one the cam shaft and crank) to time the engine. I believe 2004 is the last year of this style pcm and reluctor. Any of these years from any Chrysler 3.7 platform will just drop in with swapping accessories as needed, block and heads are the same, oil pans and intakes can vary, so need to be swapped as required.

2005-2012 3.7 from any Chrysler platform will work, different reluctors and pcm from the early KJ but the same 05-12. Block and right cylinder heads are the same, left cylinder head may or may not be ported for a egr pathway. Those without egr have no problems because it can be blocked off. Those that need egr should look for a later year engine/cylinder head.

Any year 3.7 can be used if reluctors and egr heads are swapped as necessarily.

Far as swapping another bigger engine not a lot has been done with the KJ(imho)
4.7 is the obvious choice because it’s a3.7 with 2 more cylinders and same bell housing pattern.
From what I remember those that did ithis swap successfully got a donor engine with harness and pcm, sending the harness and pcm, along with the kJ harness and pcm off to a shop to have the harness spliced and pcm programmed to work with the rest of the computers on the KJ. Many begin this project only to abandon it later.
AFAIK Not a lot of options will fit the kJ.
Some good videos and write up are out there, but like most of the cars in the last 20 years computers are so integrated it a PITA to swap another platform in.

I could be wrong but this is how I understand the kJ situation

Sent from my iPhone using Tapatalk Pro
Either another 3.7 or scrap it. KJ's aren't a builder platform worth putting anything other than stock parts on.