jeep yj motor

joshs87

Well-Known Member
Joined
Mar 22, 2008
Location
mt. holly ,nc
will the 258 exhaust manifold and intake manifold bolt up to a 4.0? and what has to be done to put a 4.0 in a 87 yj. any help would be great
 
screw using one or the other, take the crank rods and pistons from the 258 and put them into the 242. strokes it to a 4.5ish depending on bore. www.jeepstrokers.com
 
the manifolds won't bolt up and as far as swapping in a 4.0, the 4.0 probably won't bolt up to the yj's tranny depending on the year of the 4.0 and which tranny you have. however, TJ's and XJ's are everywhere and getting a donor vehicle for the whole drivetrain would be a cheap and and an easy swap, and building a stroker for the whole thing is just icing on the cake. I'm not sure where you've searched for info on all this, but www.jeepforum.com has some good info, www.naxja.org is primarily for XJ's but it has a TON of good info about the 4.0. Another thing to think about is a SBC and drivtrain would also be a fairly easy swap and probably pretty close in price.
 
MOTER

joshs87 said:
will the 258 exhaust manifold and intake manifold bolt up to a 4.0? and what has to be done to put a 4.0 in a 87 yj. any help would be great
Click to expand...

YES PUT A 4.0 IN THE YJ IT WILL BOLT UP GIVE ME A CALL AND I WILL LET YOU KNOW MORE I PUT A 4.0 IN MY 90 YJ 1-828-319-8221 MY NAME IS SHANE
 
I'm telling you, it depends on what year the 242 came out of and what he wants to bolt it up to. You just can't take a 4.0 out of a 00' and slap it in a YJ.
 
That's great, that means you took a 4.0 from an xj that also came with an ax-15 tranny and probably bolted it up to another ax-15. In 87 they didn't use an ax-15 tranny in the YJ, they used the Ba-10 or whatever the hell it was. So he'd have to find a 4.0 out of an XJ that also used the Borg tranny. On Jeepforum.com and NAXJA.org there's a bunch of write ups on how to do the conversion. Of course this is all assuming that a manual is being used, if not then I'm making an ass out of myself. . .
 
trans

whitneyj said:
That's great, that means you took a 4.0 from an xj that also came with an ax-15 tranny and probably bolted it up to another ax-15. In 87 they didn't use an ax-15 tranny in the YJ, they used the Ba-10 or whatever the hell it was. So he'd have to find a 4.0 out of an XJ that also used the Borg tranny. On Jeepforum.com and NAXJA.org there's a bunch of write ups on how to do the conversion. Of course this is all assuming that a manual is being used, if not then I'm making an ass out of myself. . .
Click to expand...

my 90 yj come with a ax15 trans factory
 
whitneyj said:
That's great, that means you took a 4.0 from an xj that also came with an ax-15 tranny and probably bolted it up to another ax-15. In 87 they didn't use an ax-15 tranny in the YJ, they used the Ba-10 or whatever the hell it was. So he'd have to find a 4.0 out of an XJ that also used the Borg tranny. On Jeepforum.com and NAXJA.org there's a bunch of write ups on how to do the conversion. Of course this is all assuming that a manual is being used, if not then I'm making an ass out of myself. . .
Click to expand...


Dude, did you not read this post, he clearly states the your truck would've been a pretty simple swap but the diferences are in the original posters '87 model. What's sad is that you quoted what you clearly niether read or absorbed.
 
I never said that the swap wasn't possible, or even hard, it is a relatively easy swap, all I was stating was that the ease of the swap depends on the year 4.0. Then I threw a couple sites out to help research. I'm done arguing, if I'm in the wrong, so be it, either way I gave my .02.
 
i do have the ba-10 it is not that big of a deal i just found a good deal on a 4.0 to go in my jeep so i could drive it until i got my 360 built if it was a direct fit then i was going to get it but i dont want to go through a bunch of trouble to get it in just to have to redo it all in 6 or 8 months to put the v8 in. but just to let you know i am not going to use the ba-10 with the v8 i am looking for a ax-15
 
a better option would be an nv3550 or nv4500. The ax-15 isn't a bad tranny and is pretty easy to find. you're using a chrylers 360?
 
have you checked what the AX-15 can handle as far as torque? That AMC 360 is going to be pretty torquey. . .
 
I dont think the AX-15 will handle the AMC 360 IMO. The AX-15 was standard with the 4.0 YJ motors. As with the NV3550 on the TJ 4.0's. You might as well go all beef with the NV4550. But if you want a budget build try the AX-15 till it blows out. Good luck man!
 
Back
Top