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Gen III hemi in RC install question

9K views 33 replies 12 participants last post by  79Rammer 
#1 ·
I have a chance to get an 08 5.7 hemi, tranny and transfer case out of a rollover total.  The rig had 43,000miles and was in top shape.  I would really like to be able to put the whole takeout in my 88' RC.  Are there any aftermarket wiring and electronics available for this.(the wiring harness is missing on the rollover)  Also I know the shaft attachment out of the transfer case is on the opposite side of my front differential.  Looking at the TC it looks like the end can be rotated,  can it?  If not will my TC connect to the newer trans?  I have looked back several months on the site and cannot find any threads on this, was surprised to not find any mention of this swap.
 
#2 ·
The swap is possible.

There are a number of sites that offer wiring harnesses for the engine controls.  I do not believe you can switch sides with that transfer case since it will be upside down and not oil properly. 

You also need to rig up the fly-by-wire gas pedal assembly.
 
#3 ·
#4 ·
Should be able to use the earlier year electronics on it without a problem and not have drive-by-wire and instead a cable.

At worst, the solid axle 4.7 Grand Cherokees had a tailhousing that will mate to the old transfer cases or the Dakota/Durango tailhousing. From there it's just matching the input to the transfer case, a 241 should go behind it and retain passenger's drop.

Transfer cases can interchange between those 500/518, 42RE, 44RE, 46RE, and (5)45RFE transmissions, but I'm not sure how mounting a transfer case from behind a 727 would work. There's several different input shaft lengths for them.
 
#6 ·
wejohns said:
thanks for all the replies. I teach welding in a tech center and as such I am off for 2 months during the summer. I am seriously considering undertaking the project this summer.
The reason most people don't do it is because it's not a big step up in power, ability to make it, fuel economy, or reliability.

The best thing to keep costs down would be staying as factory in wiring as possible with the early wiring. The earlier motors are more common to see the rod failures in.
 
#7 ·
85 Royal SE Prospector said:
The reason most people don't do it is because it's not a big step up in power,
Let me get this straight, you are saying a Hemi isn't a big step up in power vs. a LA engine?

88 318 TBI - 230 hp and 280 lb/torque

88 carbed 360- 240 hp and 295 lb/torque

08 Hemi - 345 hp and 375 lb/torque

I deem 100+ hp and 80-95 lb/torque increase in a similarly sized engine a big step up, and that's not including all around better drivability.
 
#8 ·
i don't think i would touch the engine without hearing it run first. i know someone on another forum bought a roll over with only 50k on it without hearing it run and they kept running into problem after problem. 3 years later and they still don't have a running truck.
 
#9 ·
KThaxton said:
Let me get this straight, you are saying a Hemi isn't a big step up in power vs. a LA engine?

88 318 TBI - 230 hp and 280 lb/torque

88 carbed 360- 240 hp and 295 lb/torque

08 Hemi - 345 hp and 375 lb/torque

I deem 100+ hp and 80-95 lb/torque increase in a similarly sized engine a big step up, and that's not including all around better drivability.
Yes, real-world on the pre-'09 motors there just isn't a big step up in power and there simply isn't a big step up in power-making potential on any of them that I've ever seen. The ones making big power are boosted large cube motors, not stock N/A 5.7s.

Better drivability is if you don't already have MPFI. Because this swap's a lot more involved than a swap to the other late model injected Dodge motors, they can't be discounted. All the extra power and torque is at higher RPMs, not unlike a cam swap with head/intake work.

What a 5.7 does a 318 or 360 can do. The reality is it's not all-around better in every single way.
 
#10 ·
85 Royal SE Prospector said:
Better drivability is if you don't already have MPFI.
Well, he doesn't already have MPFI, which is why I stated it.

Because this swap's a lot more involved than a swap to the other late model injected Dodge motors, they can't be discounted.
What?

All the extra power and torque is at higher RPMs,
A Hemi's hp/torque peak is indeed at a higher rpm, BUT! it puts out more hp and torque across the WHOLE rpm range than a Magnum, and even morseo than an LA. When a Hemi is at the same RPM that a magnum peaks, it has more power and has even more usable rpm to go.
 
#11 ·
85 Royal SE Prospector said:
The reason most people don't do it is because it's not a big step up in power, ability to make it, fuel economy, or reliability.

The best thing to keep costs down would be staying as factory in wiring as possible with the early wiring. The earlier motors are more common to see the rod failures in.
What are referring to when you talk about staying with factory wiring and early wiring? Are you talking about the wiring harness from a donor vehicle of the same year. I also thought 08' was the year the mpg took a leap up? I had considered a 5.9 magnum but I really want to mpfi, not wanting to go the 4bl route. I have been under the impression there is no aftermarket electrical stuff available to be able to make the swap
 
#12 ·
KThaxton said:
Well, he doesn't already have MPFI, which is why I stated it.

What?
Really? The 4.7 and 5.7/6.1/6.4 have wiring that is fairly swap-prohibitive, the motors they replaced and that ran alongside them are very good swap candidates.

KThaxton said:
A Hemi's hp/torque peak is indeed at a higher rpm, BUT! it puts out more hp and torque across the WHOLE rpm range than a Magnum, and even morseo than an LA. When a Hemi is at the same RPM that a magnum peaks, it has more power and has even more usable rpm to go.
It's not a simple, cheap swap with nothing but benefits. With "all the usual mods" they're fairly close. And as far as actual usable power in the trucks, they're really close.

wejohns said:
What are referring to when you talk about staying with factory wiring and early wiring? Are you talking about the wiring harness from a donor vehicle of the same year. I also thought 08' was the year the mpg took a leap up? I had considered a 5.9 magnum but I really want to mpfi, not wanting to go the 4bl route. I have been under the impression there is no aftermarket electrical stuff available to be able to make the swap
I don't think '08 was a year they brought economy up unless it was in the ratings. Thought it was '10 or '11 they started using 6 spds of the auto. All the Hemis before had 5spds in the autos. MDS was started earlier than '08 for the trucks. Earlier (like '02-'05) Hemi trucks didn't have drive-by-wire pedals from my understanding.

A Magnum swap is very possible with MPFI. They came with it. A lot of mods that help them are computer-friendly. There's no spend 3x what it's worth injection options, but modifying stock or the usual aftermarket sources are certainly an option. (FAST, Megasquirt, etc) Still a lot of support out there for them, and a lot of the stuff is starting to turn hands used much cheaper than before.
 
#13 ·
85 Royal SE Prospector said:
Really? The 4.7 and 5.7/6.1/6.4 have wiring that is fairly swap-prohibitive, the motors they replaced and that ran alongside them are very good swap candidates.
Yes, really. You're not making much sense.

It's not a simple, cheap swap with nothing but benefits. With "all the usual mods" they're fairly close. And as far as actual usable power in the trucks, they're really close.
Sheesh, it's hard to tell if you are in this conversation or your own. What I said is 100% factual, your response is well, not really making much sense either. As I said, a stock Hemi has a lot more power than a stock LA. Why are you talking about usual mods and "nothing but benefits"?
 
#14 ·
I've driven them all, 360 4bbl's, 318/360 TBI's, and a ton of 318/360 Magnums. Unless you do some serious modding they don't compete with the Hemi's. Finding low mileage Magnums is pretty rare now too.

I am not sure where the constant negative attitude comes from on these Hemi swaps. Drop the money on a aftermarket harness from Hotrodlane, get a factory computer, Magnum era tank and fuel pump, fuel lines, some version of cast iron manifolds, get a drive by wire pedal out of a junkyard, and build some engine mounts. It is the next upgrade I am doing to my Ramcharger. Are there more powerful engines sure, but a stock Hemi will make any Ramcharger a joy to drive IMO.
 
#15 ·
KThaxton said:
usual mods and "nothing but benefits"?
So you wouldn't sooner drop $2500 buillding your motor than swapping to a questionable JY one? The 100hp difference is in a way you yourself have often said is not worth doing to a 318/360. Or are you a big advocate of larger cams, stall converters, headers, higher-RPM intakes, and power high in the RPM in a truck now?

The 5.7's not a motor that is every bit as reliable, torquey, cheap to obtain/maintain/modify/rebuild, compact, and fuel efficient with 100 extra HP. It's a few of those things, but it's also not many of them.

79Rammer said:
I've driven them all, 360 4bbl's, 318/360 TBI's, and a ton of 318/360 Magnums. Unless you do some serious modding they don't compete with the Hemi's. Finding low mileage Magnums is pretty rare now too.
Somewhat, but most 150k- motors are extremely usable. Fewer 5.9s out and about with good miles, but the motors needing rebuilt are going like they ought to. Most cheap 5.7s need rebuilt if the blocks are even usable.

79Rammer said:
I am not sure where the constant negative attitude comes from on these Hemi swaps. Drop the money on a aftermarket harness from Hotrodlane, get a factory computer, Magnum era tank and fuel pump, fuel lines, some version of cast iron manifolds, get a drive by wire pedal out of a junkyard, and build some engine mounts. It is the next upgrade I am doing to my Ramcharger. Are there more powerful engines sure, but a stock Hemi will make any Ramcharger a joy to drive IMO.
Yes, stock they've got more power. But the swaps are not in any way cheap. If you lose steam half-way through like a lot of swaps do or hit a lot of snags, you have nothing but parts. If you do that on a Magnum swap, you gained 50-70+ HP over stock and can have a running truck again in a hurry.

It's a swap that honestly, you're only doing for the name and coil packs. Just to have MPFI and drivability, it's expensive and not worth doing. For the price the 5.7s are still going for, a Magnum could be built and modded. It's not a swap for everyone, and there's no large gain in it.
 
#16 ·
85 Royal SE Prospector said:
So you wouldn't sooner drop $2500 buillding your motor than swapping to a questionable JY one?
Who is talking about cost? well, besides you? I questioned your statement about Hemi's not having much power over a stock LA, well, they have a considerable amount of more power. This is the only arguement I am making. You are bringing other things into which I am not disputing nor is the OP asking.

The 100hp difference is in a way you yourself have often said is not worth doing to a 318/360.
didja see the part where I said they have more power across THE WHOLE RPM range? The discussions we've had in the past for modifying LA's would have cut bottom end power to raise upper end. Do you see the difference? I thought I made that clear.

Or are you a big advocate of larger cams, stall converters, headers, higher-RPM intakes, and power high in the RPM in a truck now?
See above, you are ignoring some of the facts, but just for good measure....a Hemi has more power across the whole rpm range. More than a Magnum, way more than an LA.

The 5.7's not a motor that is every bit as reliable, torquey, cheap to obtain/maintain/modify/rebuild, compact, and fuel efficient with 100 extra HP. It's a few of those things, but it's also not many of them.
So it is not these things, but then you say it is some of those things? You see why I always say you say weird shit? Further, who is asking or disputing the other stuff? Please read my posts, I am disputing your power claims, none of the other items you listed.
 
#17 ·
KThaxton said:
didja see the part where I said they have more power across THE WHOLE RPM range? The discussions we've had in the past for modifying LA's would have cut bottom end power to raise upper end. Do you see the difference? I thought I made that clear.

See above, you are ignoring some of the facts, but just for good measure....a Hemi has more power across the whole rpm range. More than a Magnum, way more than an LA.
There is not a large gain in low-mid range if there's any at all, not even close to that 100/70 figure. After the Magnum's stock operating range there is a noticeable gain, but before it's low and the peaks are 1400 RPMs higher, just like modifying an LA/Magnum to those power levels. How else do you think they're picking up 100hp with less CI? Nothing but boost and RPM can increase power and torque with less displacement and identical stroke.

Okay, maybe this is easier to understand. It's an expensive motor with QC issues, uses more expensive oil, is larger in every dimension, is negligibly lighter, gets very similar gas mileage in the same circumstances, and gives up low-end to have the peak power/torque it has.

Getting back on topic after all that. The 6.1s are bullet proof and can sometimes be a relatively small step up from a 5.7 with all the wiring and accessories from a Jeep, especially considering the 80HP bump and that the internals are decent.

The trans/transfer is different. The (5)45RFE is actually a really strong transmission in its torque rating though electronics are weak and its torque rating is not high in terms of built motors- should be fine for any N/A Hemi driver besides maybe some wicked cammed 426s. The 727/518 is a lot stronger, but likely neither will match the mpg of the (5)45RFE- and the 45's geared to make a truck come off the line and cruise strong in OD. The NAG-1s (stock 6.1 trans) are pretty decent, but I have no idea of any passenger drop transfer case that bolts to them at all. The old transmissions lose less power through the driveline as well. A flexplate is needed to mate one to a 4.7/5.7/6.1/6.4.

If you go 5.7, make sure it runs out really good. There's great ones and bad ones.
 
#18 ·
if u can hear the motor run sound good has good compression heck if u have the time
do it the genIII hemi has the same bell housing maybe u could use ur old drive train. Not
mistaken the 5.7 has a 3.58 stroke and 6.123 rods good tq still .  allpar has alot on the genIII
hemis
 
#19 ·
85 Royal SE Prospector said:
How else do you think they're picking up 100hp with less CI?
This will tell you. http://www.moparmusclemagazine.com/techarticles/mopp_0602_new_dodge_hemi_engine_information/viewall.html

Okay, maybe this is easier to understand. It's an expensive motor with QC issues, uses more expensive oil, is larger in every dimension, is negligibly lighter, gets very similar gas mileage in the same circumstances, and gives up low-end to have the peak power/torque it has.
It does get better mileage and it does NOT give up low end torque compared to a Magnum or LA. Where are you getting this from?

Here's some real life experiences.

http://dodgeforum.com/forum/3rd-gen-ram-tech/152361-5-2-magnum-vs-5-7-hemi.html
 
#21 ·
The hemi wins over the magnum period. I did the magnum swap. Carbed now but will have efi later this summer. I have a Hughes cam in it. It runs great but still gets 12 MPG. I might see 14 at best with efi. Factory efi. Everything I read about the self learning efi says mileage is not much better than a Carb. Now I can pick up 25hp and 2mpg with Hughes airgap efi manifold and better t-body. That's about $850. Plus the cam I already bought($280). I need headers to really take advantage.

A stock hemi is still making more power and getting better MPG if you get the mds computer. The cost of that cam/intake will about cover a custom harness. 09-up 5.7s make 370 or 390 hp(car/truck). 21mpg in the 1500. Better areo but 1000+lbs heavier than our trucks. There are lots of 200,000 mile hemis on the road already so forget the reliability myth. I worked for Mopar for 15 years and have worked on/sold both. Its not close except for cost unless you find a deal.

If I can't do the 4bt swap down the road I will go to a hemi.
 
#22 ·
where exactly do you see a hemi getting 21mpg? most people i see on other forums are getting about the same 14mpg every other v8 dodge gets.

my 93 with a 318 magnum has got as high as 18mpg with me doing straight highway driving. but was averaging 14-16mpg with me and my lead foot around town.

personally i would not touch those new hemi engine. the overall cost of the swap is really just not worth it to me. a well tuned/maintained fuel injected magnum can be just as fun. i know i have been flooring the gas peddle in my 93 a lot lately and it gets up and goes pretty good especially the 40-70km/h in first gear. 
 
#23 ·
MDS 1500s will get 20+MPG all day long with the cruise turned on. Witnessed it multiple times. Our 09 2wd at Midway Chrysler loaded with body parts would get 19mpg going from SD to Temecula each day. 120 miles round trip. My friend's 2010 4x4 got 17mpg towing 4 ATVs from SD to Glamis and back. So yes, the mileage is much better. That work truck was stock, the 4x4 had an air raid intake and flowmaster exhaust.
 
#25 ·
I agree, the Hemi wins hands down. I don't know why this is a debate. Is it pricey to swap one? It can be, yes. The benefits are certainly there. The Magnum is good/decent, but it's not got much on the newer tech IMO. Then you get into modding it? Factory PCM just won't cut it.

And, if you use this http://nutterracingengines.com/hemitronix/hemitronix_background.html the fine tuning you can do is head and shoulders above anything a 5.2/5.9 or factory Chrysler programming will ever do. That is THE setup to have.

5.7/6.1 Hemi and GM LS PCM running it...now that's a true thing of beauty.
 
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