So after 140K miles or so, the 2.5L in my friend's YJ is dying. He's looking at swapping in a 318.

Now, I know that you don't really want the 2.5L 5 speed behind anything but, well the 2.5L. He's bound and determind to bolt it up though. So aside from the fact that the tranny will probably puke itself either when he starts the 318 or shortly thereafter, can that 5 speed even bolt up to the 318?

Also, would the transfer case have to change if the transmission is changed?

Here's a list of givens I know of:
1) New radiator
2) New fan shroud (possibly, not 100% sure)
3) New motor mounts

Any links to sites/posts of people who have done this in a YJ?

I do not know of any adapters to the AX-5 except for one Advanced adapters has one to bolt up to a Chevy V8, but that wont help you any. Almost any transmission can be made to fit up to the NP231 T-case, manuals and auto's. Check out advanced adapters!
http://www.advanceadapters.com/
I am currently swapping in an NV4500 behind my 4 banger

hey I am looking to build a 86 comanche, and turn it into a prerunner. any 2.5's that are not fubar, I will take with a smile

Well i will have a 2.5 in a couple of weeks cuz im puttin a 6 cyl in it we just have to pull out the six put the new cam and a couple things in and clean it up then put it in my 94 so i will have the 2.5 trans and possibly the transfer case. the 2.5 is fine the trans is ok its auto tho and im not sure if were keeping the transfer case or not

Not sure about the 318 at this point, being a carb'd motor I don't know how it'd fair passing emissions being some of the stuff that was on the 2.5L is now completely absent.

What about the 5.2L (fuel injected 318) or the 5.9L (fuel injected 360) as a swap?

You guys have emissions on older cars? Double check your emission laws. Here in IL they stopped testing OBD 1 equipped vehicles the end of 06.

Not sure about the emissions part. I'll have to check that one out.

Out of curiousity, about how much would a decent, but tired (probably could use a rebuild, but not in critical need of it) 350 cost? That motor seems like it'd be the easiest route to go.

Also, let's throw in a GM 5 speed to make it easier (ie no transmission adaptors). In that case, would the speedometer cable have to change? Also, would the transfer case need to be moved back? And to double check, will the transfer case work with the V8 or is it like the tranny where it only really does a decent job with 4 banger?

Just wondering, how would a T5 fair in a Jeep? Would it even be possible to use a 2wd T5 in a 4wd Jeep?