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I am new to the forum, and wanted to get some input on my idea. I have a 2005 GC WK with the 3.7l V6. I have contacted Chrysler and foudn that i have the NAG1 Tranny(which is the tranny in the limited version that have the 5.7L). What would I need, parts wise, to do the swap other than buying the 5.7L on ebay or craigslist? Torque converter, engine mounts, etc...

Any help would be great!
 

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Dude,
This a great idea. I have an 06 3.7, so its in my best interest you succeed so I (and others) can follow your footsteps.
So here are my thoughts.
First I'm guessing you are getting a complete 5.7 GC Hemi engine. Meaning with with intake and exhaust manifolds, throttle body, wires, etc, etc. Since the accessories from your 3.7 will be basically useless. I would guess you want one from an 06 model or maybe a crate engine. Not sure if the 5.7 was offered in 05.

Now you have 1 obstacle you need to be sure about. The transmission. On the 3.7 GS's the transmission is a model 5-SPEED AUTO W5A580 (DGJ), while the 5.7 GC's came with a 5-SPD AUTOMATIC 5-45RFE (DGQ). So if the engine fits then you're in good shape. The rear axle ratio is also different, but that should be irrelevant.

Then make a list. I would start with these obvious items:

1) Mounts: Shouldn't be a problem since the 5.7 mounts should go into the engine bay without mods. No welding or grinding

2) Fuel pump: I would guess the 5.7 needs more fuel delivered. Not sure the fuel lines need attention
3) Radiator: Most likely a larger radiator is needed, maybe with different hose connections, and you might need better fans. But a junkyard or aftermarket parts can solve this.

4) Exhaust: Down pipes and cat converters should be different. I would bet the only thing you can salvage from your 3.7 is the muffler and the pipe behind it.
5) ECU: Important, but should be plug and play. I would recommend you get the 5.7 from an 06 and get the ECU that goes with it. It should be that simple

If all the above works then you should be in good shape. I don't see any other item needed. But then again I've never done this.
From the top of my head if it's a 5K to 7K investment then it maybe worth it and fun too. Otherwise you would have to weight vs trading your 3.7 for a 5.7, but there's not much fun in that.

Keep us posted
 

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it could be cheaper in the long run to trade for a v8 and pay the difference. and it would be a hell of alot easier. i would only do what you are doing if i had a hot hemi or a 6.1 or something better than the standard 5.7 hemi
 

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a stock 4wd hemi wk weighs 1500 lbs more than a 5.9 zj, gets similar mileage, and doesnt accelerate as well. so if you want to do all that work to get passed by a 98, do it
 

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Don't listen to the pesimists (i think i spelled it right)
No one wants a carburated old engine from the 90's
However, i learned that the transmission on the 3.7 is the same that on the 6.1 SRT (unless what i read was wrong, and i'm thinking it is) Just something else to consider.
 

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Don't listen to the pesimists (i think i spelled it right)
No one wants a carburated old engine from the 90's
However, i learned that the transmission on the 3.7 is the same that on the 6.1 SRT (unless what i read was wrong, and i'm thinking it is) Just something else to consider.
no one suggested a carb engine swap. or a 90's engine swap.
 

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no one suggested a carb engine swap. or a 90's engine swap.
Good. So lets all help the man in answering his question.
I could be wrong but i dont think he's asking to have his idea shot down by someone claiming its pointless since he believes a 90's cherokee will smoke any 5.7 powered GC.
I for one want to see him swap this engine, be it a 5.7, 6.1 or hell even a 4.7. Show the man some love!
 

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You might want to start by looking under the hood of a Hemi to get a visual cue of what looks different. I'm not familiar at all with what it looks like under the hood of a WK, but if you look at other models, not many engine accessories are a direct swap with different engines.

Then start cross referencing part numbers for the V6 and Hemi models for everything under the hood (power steering pump, radiator, intake, etc.) and find out what the differences are. I'm sure the size of the radiator will be the same -- but will the coolant hoses match up? Don't forget that all the electronics/wiring will likely be different, too. Everything will probably ultimately bolt in, but due to the size of the Hemi, I wouldn't be surprised if enough stuff is different to where getting a donor WK would be the easiest option to perform the swap. Sure you could probably find a wrecked WK and do the swap, but unless you are swapping engines just for the sake of doing it yourself, you may find it cheaper and even easier to just trade/sell what you have and get a Hemi version.

As for the acceleration of Hemi vs. 5.9L...who cares? The OP will find more than enough power out of the Hemi for his application. If he really cares about acceleration, he might as well find a way to put in a Gen III/IV GM V8 (LS1, LS2, LS7, LQ9, etc.).

Oh an another thing to consider is that IIRC in my state, it's illegal for 96 and later vehicles (at least without jumping through hoops) to swap in an engine older than the vehicle.
 

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Dont forget the springs and shocks from the donor Jp. The hemi weighs a bunch more than your engine and you'll have significant lowrider look in the front.
 
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