How hard is it to upgrade a 4.0 to a v8 say a ford 5.0? -
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post #1 of 3 Old 12-31-2013, 09:05 PM Thread Starter
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Join Date: Dec 2013
Location: Norfolk
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How hard is it to upgrade a 4.0 to a v8 say a ford 5.0?

I'm only thirteen and I want to have a jeep tj when I'm sixteen but the naturally aspirated straight six just doesn't cut it for me. I saw a cj7 in a shop with a real nice 350 and fiberglass body. The mechanic said its built to launch but I don't have that kinda of money to spend. I was just wondering if anyone knows if its hard to do or requires extensive welding for a v8 engine swap. I'd put in a 5.0 out of a fox body mustang or something that size. And should I replace the current transmission too? As well as upgrade the axles to like blazer k5 ones so they can stand up to the extra horses?


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post #2 of 3 Old 12-31-2013, 09:40 PM
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1989 YJ Wrangler 
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Location: Rathdrum
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The Ford 5.0l engine is a great engine for a Jeep. That being said...
Well there is a lot of work involved. You have to find out what your states smog laws require. Then you have to find a engine that works with the laws. You need to find a trans that works with the engine, a t-case that works with the trans. You have to build mounts for then all. then you have to install them. The stock jeep axles will not survive the added power. So now you have to find axles that fit the vehicle and work with the t-case. Then you can swap them in. At that point you are ready to start to run it and work all the bugs out.
For an experienced mechanic and welder/fabricator this can take from a month to eight months once everything is rebuilt. It is very commonly a $8,000 project. A rebuilt 4.0l has pretty good power and can more easily be modified to create more hp/tq. This means less money and no fabrication. As well depending on the axles already in the Jeep you can just get chromolly shafts and gears and be good to go. If it has a BA/O transmission get a AX15. With those modifications you have a good vehicle with a lot less cash and skill needed. You can do most of the work with the help of the Haynes or Chiltons manual in your drive way and its all bolt ins. The only exception is the ring and pinion swap that you will need to match to your tire size. I'm not trying to make it sound worse than it is. You do some research and a lot of reading and decide for yourself. Good luck and have fun.

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post #3 of 3 Old 01-05-2014, 09:09 PM
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1992 XJ Cherokee 
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Put a 350 in an xj once. $5000 in parts. My dad owns the shop so no labor. Took 2 months of labor with 3 of us. Ended up selling it. Couldn't feed it.
Helped a close friend last year swap a 4.2 out of a cj for a 304. That wasn't ad bad.
But like stated above. If you do a heavy stroke to the 4.0 and some tranny work you'll be happy and its sooooo much easier and affordable.
cjs are easier for v8 swaps since some had them.
I run a 4.8 stroker in my xj with 35's. I'm in love with it and won't even consider a v8.
There's a saying here...if you want to go fast get a mustang. If you ant to go anywhere get a jeep
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axles , engine swap , horse power , upgrades , v8

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