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Discussion Starter · #1 ·
Here is the problem. My stock 258 has 96,000 Miles on it now. I want to do a Fuel Ijection swap on it from a 4.0. I do not knwo if I should rebuild my 258 with the 4.0 head and all or find a fairly good 4.0 and do a straight up swap. Time and work for the project is not an issue for me.

Sorry, my YJ is a 90, not an 87.

 
G

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well if time and work wasnt an issue I would vote to rebuild the 258 and swap the 4.0 head. Then maybe if the money was there look at FI if the money wasnt there Look for something like the webber where you can run a stock air box to pass visuale inspection and ditch the POS carter my rational be hind this is you know the history behind the 258 you already have. No point putting in a 4.0 that is questionable in history/maintinece.
Just my $.02

Travis
Lots of goodies!
 
G

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i have a 4.0 with 170,000 miles on it. the rest of the jeep is giveing me [censored], but it isn't. its a beautiful thing. i read a little about both options, just for kicks, the general opinion seems to be the 4.0 cost more money but is worth it. 2000 for the FI swap, 2500-3000 for the 4.0. but the 4.0 is cranking out 180 hp, while the fi/header swap should get you 40 i think. and i've got low end torque like crazy. I don't know alot, but my own opinion, owning a high mileage 4.0, is that it kicks ass. plus i had a 258 once and it sucked. and then the carb caught fire and the whole jeep blew up. which was good.
 
G

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The 40hp boost mentioned in the last post is the average gain when swaping the 4.0 head and keeping the carb. If you look at the Tim Weaver article, he and others who have done the full FI swap, mention that the HP is higher than a stock HO 4.0 motor.
The 4.2 is know for being a better off-road engine because the power and torque is all found in the lower RPM band whereas the 4.0 reaches it's power in the higher RPM's. The down fall of the 4.2 which gives it the bad wrap is the Carter BBD carb which you will doing away with.
A 4.2 built with the HO 4.0 head and FI turns out to be a better motor giving you the best of both worlds. Either way you are going to need to retro fit the computer and such for both choices so one isn't really easier than the other.


'88 Sahara, 4.2 that runs thanx to every Cheap trick on this board. The rest is getting there!/wwwthreads_images/icons/blush.gif
 

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Discussion Starter · #7 ·
I like the idea of making the 4.0 a stroker. I Will get the comeplete 4.0 engine computer and all from a local yard. Either way i will need to rebuild a motor. I am thinking of getting the 4.0 and possibly stroking it. Sounds like a lot of fun.

Sorry, my YJ is a 90, not an 87.

 
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