is it a straightforeward swap? I can get a free 258 out of a 73 SJ and a damn near free 91 XJ limited.

would this work?

Is it a fuel injected 4.o? If it is, it is MUCH easier to do the 4.0 head on the 258, otherwise you have to convert the system to deal with the carb adn shit. Do a search, a month or two ago I did this exact swap in my YJ. :beer:

I wouldn't expend the energy to put a4.2L in anything except the scrap heap. Is the 4.0L history?
regards, as always, jefe

I agree Jefe, but if he has a blown 4.0 and a running 4.2, as I did, it only costs about $80 in gaskets to make a running combo ;)

However, MKBRUIN, if oyu wanna put a complete 258 with carb and shit in it, I would agree, dont bother.

I remember your engine problems kieth, I never saw how you resolved the issues.

I am just getting info on this deal...the guy said it had a blown motor. from further correspondence, it sounds more like an alternator!!!!!!!!!!!!!!!!:D :D :D

God I love JU!

do you have a writeup on the 4.0 head on teh 4.2? is it a straight changeover with a gasket kit? or is this all in your previous posts and I can just search for it.....

Be careful, alot of their members lurk here, and vice versa. I would hate to see you lose a killer deal ;)

Here is the write up I used the most. I got tons of help from sundowner, rockbuggy, jaffer, adn others for

info.http://monsterslayer.com/jeep/40Head/40Head.htm

Search, their are more, but here are a couple of the threads I got good stuff from.

http://www.pirate4x4.com/forum/showthread.php?s=&threadid=46138&highlight=4.0+4.2

http://www.pirate4x4.com/forum/showthread.php?s=&threadid=53227&highlight=engine

Hey Keith, what did you do for the water jackets? Half the writeups say they need to be brazed, the other half say jb weld or just let the head gasket do the work

I used Quiksteel....they leak :( Get em brazed, do it right....I just had 4 days left to get it running, so I cut corners and now I leak coolant on starup.....it goes away once I am at running temp though.