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Unread 03-07-2011, 03:09 PM   #1
danderson3789
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YJ Hemi Conversion

I picked up an 87 YJ recently and I want to install a 5.7 liter hemi and tranny from a Dodge ram into the YJ. Someone had already swapped the 4.2 liter carb motor for a 4.0 fuel injected motor. The jeep runs fine, so I am in no hurry to get the swap done. The hemi, tranny, electronic gas pedal and all the electronics are sitting in a working 83 Dodge dakota, so I know that all is good and everything is present.

I have stock axles front and rear and a stock transfer case.

Two questions. First, any advice on the motor swap, any pictures, any big concerns, please HELP.

Second, I know the rear axle simply will not tolerate all that power, especially if I end up at the sand dunes (which is my goal). I can change the rear axle for a Ford 8.8 and keep my bolt pattern, gain disc brakes and stay fairly consistent on width. I have a friend who has a Toyota axle from a Toyota truck that he thinks is great. The axle is not as wide and the bolt pattern is 6 on 5.5, I believe. The good news for the Toyota axle is that it has my gears already in it with a lock rite locker and the price is great. I wonder if I am selling myself short on the Toyota axle. I really do not know a lot about rear axles, especially in this application.

Any thoughts on rear axles capable of handling a 5.7 liter hemi.

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Unread 03-07-2011, 04:26 PM   #2
Jabo
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Go with the ford 8.8 same bolt pattern and just about the same length, maybe 1/2" on each side shorter and disc brakes are much better.
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Unread 03-07-2011, 04:56 PM   #3
TheNewbie
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8.8 rear, and the front D30 should be fine up front unless you get stupid.
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Unread 03-07-2011, 05:00 PM   #4
cheese_man
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it is easier to swap in a ford 351 windsor engine

just use amc engine mounts ( the wiring for the engine is already there )
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Unread 03-07-2011, 05:23 PM   #5
Nibbley15
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Quote:
Originally Posted by danderson3789 View Post
I picked up an 87 YJ recently and I want to install a 5.7 liter hemi and tranny from a Dodge ram into the YJ. Someone had already swapped the 4.2 liter carb motor for a 4.0 fuel injected motor. The jeep runs fine, so I am in no hurry to get the swap done. The hemi, tranny, electronic gas pedal and all the electronics are sitting in a working 83 Dodge dakota, so I know that all is good and everything is present.

I have stock axles front and rear and a stock transfer case.

Two questions. First, any advice on the motor swap, any pictures, any big concerns, please HELP.

Second, I know the rear axle simply will not tolerate all that power, especially if I end up at the sand dunes (which is my goal). I can change the rear axle for a Ford 8.8 and keep my bolt pattern, gain disc brakes and stay fairly consistent on width. I have a friend who has a Toyota axle from a Toyota truck that he thinks is great. The axle is not as wide and the bolt pattern is 6 on 5.5, I believe. The good news for the Toyota axle is that it has my gears already in it with a lock rite locker and the price is great. I wonder if I am selling myself short on the Toyota axle. I really do not know a lot about rear axles, especially in this application.

Any thoughts on rear axles capable of handling a 5.7 liter hemi.
Sell yourself short on a Yoda axle? They will take a beating and come back for more, and yes it is a 6 on 5.5 Their weak point is when you gear them over 5.29 (not enough teeth from the pinion to the carrier); but running 4.10 they are very hearty. I must admit I am also a Yoda finatic also. I would love to have that locker from that axle though if you go with a ford 8.8 ;-) Seeing as you would have to get new rims if you go Toyota vs Ford, I have a feeling which way you are going to go with; good luck.
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Unread 03-10-2011, 09:20 AM   #6
danderson3789
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Has anyone actually put a 5.7 liter hemi in a jeep? the chevy 350 has been done a thousand times but i never hear anyone talk about a 5.7 hemi. ???
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Unread 03-10-2011, 09:29 AM   #7
dillonjm
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Quote:
Originally Posted by danderson3789 View Post
Has anyone actually put a 5.7 liter hemi in a jeep? the chevy 350 has been done a thousand times but i never hear anyone talk about a 5.7 hemi. ???
There have been a few into TJ's, not sure if I've seen one in a YJ. I'm sure its been done though.
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Unread 03-10-2011, 12:09 PM   #8
tobias94yj
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the 4.2 is what came in the 87YJ the 4.0 did not start until '91 for yj's.

I don't know if you mistyped but I don't think an '83 dodge had a hemi or if they made a dakota in '83. the hemi was not reintroduced until the 2000's dont know exact year and they have not put one in a dakota unless they are going to in the 2011.
I know i would not worry about the 8.8 behind a v8 but if you are concerned you could look into swapping 3/4 ton axles in it if you don't mind the full width.
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Unread 03-11-2011, 03:07 AM   #9
danderson3789
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Tobias, thanks for the input. As I stated, the 4.2 in the YJ was replaced by previous owner with a 4.0 out of a 99 cherokee. The 5.7 liter hemi came out of a dodge ram pickup and has been in the 83 dodge dakota for about a year and half. So, while you are correct that those were not factory options, they are in fact what is in both vehicles.

So, my question remains the same: Can anyone help me with some insight into fitting a 5.7 liter hemi into my Jeep YJ? I dont want to get head long into the project and realize that the firewall has to be cut away to accomodate the bellhousing or that mount locations are too wide for a simple motor mount change. Or the mounting depth of the motor would require major relocation of the radiator, etc. If someone out there has done this, even in a TJ, they should be able to give me a heads up or some helpful hints.

Thanks for the input so far.
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Unread 03-11-2011, 03:11 AM   #10
danderson3789
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one typo, 93 dodge dakota, not 83. A hemi is still not a factory option for a 93 dakota.
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Unread 03-11-2011, 04:10 AM   #11
tobias94yj
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Quote:
Originally Posted by danderson3789 View Post
Tobias, thanks for the input. As I stated, the 4.2 in the YJ was replaced by previous owner with a 4.0 out of a 99 cherokee. The 5.7 liter hemi came out of a dodge ram pickup and has been in the 83 dodge dakota for about a year and half. So, while you are correct that those were not factory options, they are in fact what is in both vehicles.

So, my question remains the same: Can anyone help me with some insight into fitting a 5.7 liter hemi into my Jeep YJ? I dont want to get head long into the project and realize that the firewall has to be cut away to accomodate the bellhousing or that mount locations are too wide for a simple motor mount change. Or the mounting depth of the motor would require major relocation of the radiator, etc. If someone out there has done this, even in a TJ, they should be able to give me a heads up or some helpful hints.

Thanks for the input so far.
I was making sure you had what you thought you had. i have seen alot of people get ripped off and lied too.
I have heard of it done in a tj more than a yj but it should not be too much different especially if you have the ecu from the 99 4.0. now most of the time it is done using a conversion kit from AEV. but if you look at other v8 swaps then you can see as far swapping engine from even chevy or ford the wrangler is pretty easy. the v8 is actually shorter than the 4.0 so no you will not need to cut your firewall. since you already have the 99 4.0 i am going to assume you have the ECU also. on Hemi swaps they make a wire harness adapter i think so all of the stock guages will work. transmission i would get would be a 5-45rfe if I was going auto. do your research but I believe a 23 spline np231 will bolt right to this tranny. go and check out advance adapter and check out the link yj hemi swap but also google search it because I know it has been done and i am sure there are write ups already.
also if you decide to do it get you camera handy and start a thread on the build because I guarantee it will be one of the most popular threads. I know I will follow it wanting to see your progress. Good luck.
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Unread 03-11-2011, 09:48 PM   #12
GottaYJ
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If you decide to do this I will be happy to do some wrenchin on it. All I need is Pizza and Beer
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Unread 03-11-2011, 10:40 PM   #13
kbfunTH
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Atomic 4x4 in Cedar Park TX does 5.7 Hemi conversions. They may be able to offer some assistance.

http://www.atomic4x4.com/
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Unread 07-31-2011, 06:29 PM   #14
CJMadd
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I'll Help with you're SWAP...

Quote:
Originally Posted by GottaYJ View Post
If you decide to do this I will be happy to do some wrenchin on it. All I need is Pizza and Beer
I'm doing the same swap, except my 1987 YJ still has the carbarated 6 cylinder in. I'm pulling my Hemi motor out of my 2001 Dakota Quad Cab, but It's a 2wd so I'm going to have to find a manual transmission. I should be able to help you with you're swap..
The first thing you'll need is the wiring pin-outs for a 1990 Jeep with a 4.0. Then You'll need the computer pin-outs for the Hemi..I can post the pin-outs on the Hemi, but it's important to know what year Hemi you have. Dodge re-introduced the Hem in 2003, But it didn't have a EGR , and the ECM and TCM were separate units. In 2004 They added the EGR and did away with the TCM combining them together in one computer. They changed the wiring pin-outs again in 2005 and added a way to get more power and re-adjust the transmission with a chip. In 2006 they changed it again , then again in 07. The best Harness and computer to use is an 04..Then you're motor can be a 03'-05'.
When I put My 2004 Hemi Rumble Bee Motor in My 2001 Dakota Quad Cab, I learned a lot about wiring Hemi's. Now I have to figure out how to make it work in a NON fuel injected Jeep. I'll probably have to use my gauges and PDC from the Dakota... Not sure , But If you want to put two threads together and post pics and info from both we can. We could probably help each other..
You can see my Dakota Hemi build thread by going to www.DodgeForum.com Search Dakota Hemi Swap. My Name on that is HemiDak-Quad. You'll find the Hemi pin-outs for 2003-2004 ECM & TCM, I think on page 8..Pics of the truck are on 10 , and there's a burnout..
Have you started you're build, or put the motor in yet ??
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Unread 10-04-2011, 01:25 PM   #15
triplej1954
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Did you do this conversion. I have an 87 YJ and I have a 2005 Hemi with an auto transmission from a wreck given to me for pulling it out. Summit sells an computer that they told me would work (have not tried yet). I am looking at doing this and if you can give any advice it would be helpful.
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