3.7 to 5.7 swap

My truck has about 181k miles on it and I was thinking about trying to swap in a lower miles hemi. I was wondering if anyone had any information about people who may have done something like this before. I just want to know what kind of problems I may have, if there might be certain trannys that are easier to put into thr truck than others and what the best tranny option would be.
I'm hoping to be able to swap in a hemi and still have it be a stick shift.

From what Ive gathered, the entire engine electrical harness, as well as the engine computer needs to be swapped. Possibly even the electrical harness inside the dash of the truck, which is gonna be the huge pain in the ass part of the project, as you'll probably have to remove the dash to do so. You'd need to find a fully complete donor truck either in the junkyard or a cheap wrecked parts truck to get all these parts. Maybe someone who knows more of the exact details of the swap will chime in.

The interior wiring harness will depend more on the options you have in your vehicle than on the engine it boasts, so not issues there.

However, LTD was right in the fact that you will require everything under the hood/truck. From the exhaust "Y" all the way to the front.

You should have a 45rfe which is the same as the 4.7L. However the Hemi runs on the 545rfe which is very similar. In fact some people have actually "upgraded" their 45rfe to a 545rfe with a simple TCM swap and flash.

As I have told others, I believe the easiest and cheapest way of getting this done is to have a donor truck you can park right besides yours and then the parts store is sitting a few feet away from where you need it... A good donor could be a truck that was totaled in a crash, but the mechanical is still good. Avoid fires, as all the needed harnesses are unusable which is the most important part for you.

So basically, it will be easier and cheaper to look for a good deal on a trade and put a little TLC on a complete truck that might need a few repairs rather than trying to achieve this swap, unless you have access to a very low cost donor, lots of comfortable space to work in, the time and desire to do this kinda work.

Hope this helps.

Good to know that I'm not gonna need to swap interior electrical harnesses, that was what I didn't wanna do. I can pickup a low mileage Hemi around here for only around $550. If I can find all the other parts reliably, and at a decent cost, it makes sense to me to go ahead and go for it on my current truck. Finding unmolested Hemi Ram's in a U-pull-it junkyard, and pulling all the parts myself should be the cheapest way to go. If my calculations are correct, I should be able to get the entire swap done for around $800. I may just start collecting parts for this soon.

Good luck finding hemi rams in a u-pull it, I was always looking for them when I was stationed down there. 3.7 or 4.7 to hemi in a modern electronic vehicle is a pain in the ass. Good luck.

Thanks. It should be mostly plug and play once the correct parts are attained. There might be a little wiring involved, but my shop manual for this truck has the wiring schematic layouts for all 3 gas motors and trucks 02-08, just in case. I have seen a few hemi ram's in the yards around this area in the past. The problem with that being when they pull the motors at the yard, they usually cut and hack the harness in the process. So it might be hard to find an intact harness. That's probably gonna be the main hangup here for me, and whats gonna determine if this is feasible or not. If I go through with it, I'll be sure to document it, to help people out with future swaps.

If the harness becomes an issue, contact hotwireauto, I know for a fact they've done factory quality harnesses for 03 hemi to 05 hemi swaps and a Liberty 3.7 to 4.7 swap.

sell your truck, buy one with a 5.7. probably the easiest (and cheapest) swap.

^^This X2

dkmesa said:

sell your truck, buy one with a 5.7. probably the easiest (and cheapest) swap.

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X3 don't **** up a running truck. Been there done that with a previous truck, an also I agree with hemi lonestar. It's harder to find an more $$$ for a ram hemi at a junkyard. Just a hemi in general. At least in my area

Thanks hemilonestar, I will check them soon. Ive been doing some further research on the swap and it seems pretty straight forward. I'm looking forward to doing the swap now. Hopefully sometime in the next few months.

Obviously buying a truck with a Hemi already in it would be the easiest route, I think that goes without saying. My truck is far too clean to give up though, for another hemi powered one, that might not be anywhere near as clean or rust free, or in Black. I searched for awhile before I found this one. Since low mileage Hemi's can be picked up from junkyards around here for about $5-600. It's more than worth it to me to do the swap on this truck.

LTDMan said:

Thanks hemilonestar, I will check them soon. Ive been doing some further research on the swap and it seems pretty straight forward. I'm looking forward to doing the swap now. Hopefully sometime in the next few months.

Obviously buying a truck with a Hemi already in it would be the easiest route, I think that goes without saying. My truck is far too clean to give up though, for another hemi powered one, that might not be anywhere near as clean or rust free, or in Black. I searched for awhile before I found this one. Since low mileage Hemi's can be picked up from junkyards around here for about $5-600. It's more than worth it to me to do the swap on this truck.

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Have you investigated retrofitting the 08+ heads, cams and intake manifold? The manifold is a definite, the 08+ cams are more plentiful than old HO's, though I haven't read anywhere yet that they definitely work. So far it's been, "I'm trying this" and then nothing else.