JKU Hemi Swap - Reference Guide & Swap Info

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Introduction & Hemi Basics

If anyone has ever spent time on the Wrangler TJ Forum, you may have seen my Gen III Hemi swap info there. I figured since I'm going through the work on my JKU, that it just makes sense to do that here as well. There are plenty of YouTube videos, some done by vendors selling swap parts (such as Jeep Speed Shop, which is who I'm primarily sourcing my part from), and some done by people trying to help others out.

Some worthwhile videos to check out:
JKB Off-Road: https://www.youtube.com/@JKB_OFFROAD_olllllllo
JK Gear and Gadgets: https://www.youtube.com/@JKGearandGadgets
Jeep Speed Shop: https://www.youtube.com/@jeepspeedshop

While I love YouTube videos, and I may even make a few of my own in those instances where I think other videos may fall short, I think there's a lot to be said of having a step-by-step forum post that can be referenced, corrected, and added to as needed. I'll be building this thread out as I go through my swap, where I'll be putting a 5.7L VVT LX Hemi and 8HP70 into my 2008 JKU. I'll have some info about the Hemi swap in My Build Thread, but the bulk of the technical information, references, and more, will be saved here for future easy reference by myself and by anyone else who needs it.

If there's something I glossed over or something you want expanded up, just let me know!

What is a Hemi?
The Gen III Hemi ("gen three", or generation three), is, as the name would suggest, the third iteration of the Mopar Hemi engine. In 2002, the Gen III Hemi was debuted in the Ram 2500/3500 pickup line, followed by the Ram 1500's in 2003. It boasted 345 hp and 375 lb-ft of torque and was immediately recognized as an excellent engine platform (it has made the "Ward's 10 Best Engine" list six times). By 2005, the 5.7L Hemi was available in pickup trucks as well as the LX-series of Chrysler-family cars.

Some say that the Gen III Hemi, commonly short-handed as the "G3" to help differentiate it from the Gen-III GM motors, is not a "true" Hemi since it doesn't have a traditional hemispherical head design. These people usually eat their own boogers and think that boys shouldn't be allowed to play with dolls. Ignore them, you don't need that negativity in your life...

Much like the GM and Ford counterparts, the Gen III Hemis took advantage of engineering and computer-aided design advancements. As a result, the Gen III retains a traditional push-rod orientation but with significant flow improvements over the previous Gen II V8 engines (such as the Magnum).

In 2009, the 5.7L Hemi received some major internal changes and an even larger use of technology. The block was new, the crank was upgraded, the cylinder heads were better and the cam got a tad more aggressive - all while sporting better power and economy. The 5.7L Ram engine - known as the "Eagle 5.7" was now rated at an honest 390 hp and 407 ft-lb of torque. Some people consider the 2009+ engines to be the "Gen IV Hemi", but this naming convention has not caught on. Most people simply refer to them as the "VVT engines".

The biggest change was the use of VCT - variable cam timing. The ECM can now vary the valve opening to optimize flow throughout the RPM range. The use of MDS - or multi-displacement system technology was continued but improved upon and matched with the VCT for significant gains in economy. It isn't uncommon for swapped rigs to push 18 MPG in Jeeps (when coupled with the Dodge transmissions).

Later Eagle updates also included a "SRV" (short runner valve), which is essentially part of the Hemi "active intake". This valve provides a bypass for incoming air and moves it from the plenum directly to the cylinder heads. The shorter route allows for more power at higher RPMs while allowing the nice long, wide torque curves of a traditional long runner.

What Hemi Should I Swap?
While some older JKU Hemi swaps indeed utilized earlier, non-VVT Hemi swaps, this has all but stopped. The VVT engines make more power, are easier to find, and are cheaper due to availability. There's no compelling reason to use a non-Eagle/VVT Hemi in a JKU swap.

That said, there are some considerations to be made for what platform you got your donor from. The donors are usually broken up into car/SUV, often referred to as the 'LX-platform" motors (not to be confused with LSx), and "truck-VVT" motors. Internally, all the engines are the same. The differences come on the exterior.

The 5.7L truck engines are often easier to find, and many include an 8HP70 if you're considering that swap as well. The truck engines have physically longer front end accessory drives (FEAD). Essentially, the water pump, power steering pump, A/C compressor, etc. all stick out further from the timing cover than car/SUV FEADs do. This means you are unable to run your OEM Jeep fan. You need to either run a manual fan, or go with the common "Camaro fan" (which is thinner profile than the Jeep fans).

LX (car/SUV) engines can reuse your OEM fan. 6.4L engines (from car or truck) must move the air cleaner to the driver side fender due to how the intakes are shaped on both. Any and all engines can be made to work, you may just need some different parts to make it all work together (more on this below).

 

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Foreword – Considerations & Project Planning
Why Hemi?
One of the first things I get asked by folks is "why a Hemi?". One of the first things Jason, the person I just sold my old 3.8L to, asked me was "why not an LS?". It's a good question that for me, has a really simple answer: integration.

[2010 5.7L Eagle Hemi that I originally bought but ended up having a chewed up cam lobe... more on that later]

The LS is a great motor and has certainly helped paved the way for "modern HP" in many classics and swap candidates. That said, the LS in a JKU has a lot of headaches. Even @rockvegas555 has said that if he were to do another V8 swap, that it would likely be a Hemi, and he's got a 6.2L LS3 with 525 horsepower and 486 lb.-ft. of torque!

The Hemi is natively part of the Chrysler ecosystem and already uses shared CAN protocols, which are easily integrated with the OEM TIPM, and offers OEM-functionality with things like cruise control, EVIC, stability/ABS control, A/C request logic, cooling fan logic, and OBD-II. Compared to an LS swap, you often need to bypass several functions, often have to manually control A/C, may or may not have functioning cruise control, and more.

Aside from some of the integration headaches, the Hemi fits well (in particular the 2009+ VVT) and now has the option of the 8HP70/75 transmissions. With the exception of the motor mounts, a modern Hemi swap can be done with nearly 100% OEM, off-the-shelf Mopar parts.

Why 8HP70?
If you want the Jeep to feel modern, fast, strong, and factory V8-correct, the 8HP70 wins everywhere except cost and wiring complexity. While you can use the NAG1 if your JKU is equipped with one, it’s older, weaker, and has fewer gears, making it less ideal for heavy rigs pushing big tires.

[A low mile, 2019 8HP70 originally sourced from LQK with TC]

The Hemi-era 8-speed autos are incredibly strong, shift fast, and offer excellent on-road and off-road drivability thanks to well thought out gear ratios. The fact that they're offered in Ram 1500s for a number of years now makes them readily available. These can be picked up cheaply from nearly any parts recycler or yard. I only paid $500 for the one above and this isn't an uncommon find.

For me, while there is an added expense and wiring integration is a bit more involved, the advantages far outweigh the small expense and hassle. Again, going back to my point above, getting 3 additional gears, with OEM integration, that runs cooler, offers better engine braking, and gives lower cruise RPMs while also a better 1st gear ratio is, for all intents and purposes, a decision that makes itself.

Intended Use & Needs
When I started the JKU project, I had a modest, but critical list of criteria:

• Overbuilt - always a long-time build approach, regardless of purpose, mainly because "I have to drive this home"
• Reliable - if I am not confident enough to drive the Jeep across the country to Moab, I'm doing something wrong
• Street friendly handling/manners - for sanity and in case the Mrs. needs to drive it for any reason
• Ability to keep the Jeep "mostly" inspection friendly - PA requires annual "safety inspections"

The Hemi swap fits well into my overall needs and vision - a reliable, daily driver than can a tough weekend warrior.

[A cartoon rendering of an actual photo of my JKU, with some artistic tweaks made]

More importantly, it's something I will enjoy driving, which I can honestly say that with the 3.8L, was not the case. While the new axles I just built and installed in my daughter's Islander have helped, driving a rig around the hills of NEPA gets exhausting. The engine is always struggling and the transmission is constantly searching for gears on hills. Throw in the fact that it barely has enough power to maintain 65 mph while towing a small utility trailer is simply not something I would deal with for long.

Budget scope
I am fortunate in that I don't have a budget limit for this build. This does not mean that I'll be going full blown crazy and am going to slap in a HellCrate (well, not yet at least), but I'm making decisions based on value, and not necessarily on cost. That said, I will be keeping track of all the costs associated with this swap and will share the total when all is said and done.

Time expectations
Right now, I'm driving my daughter's Islander around and will do so until my project is done. She's coming back from college for the summer in mid-May, so that seems like my natural target completion date, though I would prefer to have it done much, much earlier. I'm targeting a first-drive sometime in mid-March. This will give me a few weeks to work out the kinks and will be late enough into winter/early spring that weather should hopefully not be too problematic should I need to do anything outside.

 

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Full Parts List + Part Numbers

Todd at JSS has lots of BOM sheets on his site and updates them periodically. If you're doing anything but a LX-based engine and 8HP70 swap, you should head on over to his home page and find the BOM you need.

I am actually helping Liz (Todd's wife) update some of the BOM lists as there has been some confusion and I volunteered to help clean them up. I will update the link and document once Todd has a chance to work through these updates and give the thumbs up.

 

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3.8L & Transmission Removal
Best practices
Since I'm doing my Hemi swap right after doing my D60/14B swap, my undercarriage was already fairly clean. Even still, I gave it a second blast of Simple Clean and hot pressure water before tackling the engine and trans removal. Remember, more often than not, an ounce of preparation prevents a ton of headache. Spend the time to get things cleaned, and preventing dirt, oil, and grim from falling on your face makes crawling under a rig much more pleasant.

[Weather can turn quick here in NEPA, so I power washed the Jeep as soon as I was able to wheel the rig back outside following the axle swaps]

I'm sure there are a million and one different ways people have done this, so I'll simply focus on what I did. Since I was snatching both the engine + trans together, I opted to remove my entire front radiator support before attempting to do anything else. Doing so allowed me keep the cherry picker much lower than I would have otherwise, which adds to the safety factor, while also allowing me to do this inside my garage (it was in the 40°s out there!).

There's no big secret in removing your 3.8L. Make sure you get your A/C system evacuated prior to starting the work, and then it's just a matter of draining the engine and transmission oils, then draining the coolant, followed by unhooking everything attached to the radiator and condenser.

[Draining the radiator via the petcock at the front, passenger side of the radiator]

After all fluids are drained, you disconnect the wiring connected to and around the grill support, securing the wires out of the way as you go. If you have a lot of grit and grim on the connectors, I found that a quick squirt of WD-40 helps loosen things up enough to make removal much easier (and less likely to damage the connector). There are a number of "cam" style connectors. They're all different but follow the same basic order of operations - you depress the safety interlock (often near or just under the "handle" of the cam), then you slowly and smoothly rotate the cam away from the connector. Doing so pushes the connectors apart and allows for full disconnect.

With everything drained, you can now remove the radiator/condenser as a single unit. You'll have to disconnect your transmission cooler lines from the factory cooler, which means you'll likely have some spills to deal with even with good catch pan placement. Use rubber or silicon caps, as well as metal drip pans and cardboard to keep your shop tidy. It's the small things, like having ways to quickly and efficiently deal with spills and drips, that make these steps go much smoother and overall make the process much less of a headache. Plus, with quick clean-up, you won't have to worry about lying in an old oil spot on your floor when you're putting this all back together.

[Fluids drained and radiator support removed]

With the radiator and condenser out, you can unbolt your radiator support and set it aside. Now that the front end components are cleared out of the way, you'll have lots of easier access to the rest of the parts that need to be removed. My driveshafts were already off, so next up for me was the t-case. The nuts at the top are a pain in the a$$ to get to. Thankfully I removed the transmission shifter some time ago (since I will be installing an OEM Dodge Challenger shifter for the 8HP70), which allowed me to reach down through the hole in the transmission tunnel to get to them easily. You may need to drop your driveline down some to get to the top nuts, depending on what you're doing for your swap.

When removed, set the t-case aside someplace safe and out of your way. With those items out of the way, you'll need to start removing the other stuff attached to the engine: exhaust collector to manifolds (I left the manifolds on the engine as they gave a good place to throw a chain around!), TIPM, battery, heater hoses, etc. Depending on the condition of your rig, you may want to hit many of these connector points with some WD-40 or penetrating fluid ahead of time.

You'll have to disconnect some of the large engine harness connectors at the firewall, but the harness itself can stay on the engine. I did remove the starter from the engine before removing, only because I was worried that it would get hung up during the removal on the frame mounts, but it appears that this was unnecessary as that section clears nicely.

[Me being not so limber and nimble, strapping the trans to cherry picker]

At this point, I used a scissor-style transmission jack under the transmission pan, and removed the transmission crossmember. There's really not much left once you get to this point. Run your hands back and around places as you start to lift the engine out to make sure you're not forgetting something. Take your time and ideally have a helper with you. An extra set of eyes really has an advantage, though you can 100% do this safely if you take your time and don't rush things. Once lifted, never put any part of your body below the engine or transmission.

Tips
I found it much easier to get the 3.8L out by removing the driver-side motor mount from the engine block. This let me slide the engine and trans forward, giving me lots of space at the firewall and trans hump. With the mount still bolted to the engine, you'll have to lift the engine over both of the engine mounts on the frame rail to get it to clear. This makes it very tight when removing the engine and trans together, as the trans wants to constantly get caught on the trans tunnel.

Tools Needed
Aside from the obvious way to lift and remove an engine and trans, you'll only really need basic hand tools for most of this. I can't think of anything off the top of my head that needed something special I had in the toolbox.

The one item some people may not have would be a fuel-line disconnect tool. I've had this AutoZone one for over a decade now and it worked perfectly fine. It also worked for the trans cooler lines.

[Fuel and trans metal line disconnect pliers]

Weight/Balance Notes
You'll be lifting out ~600 lbs of engine and trans, so overall balance and where you lift can be a safety hazard if not done correctly. I used some heavy duty chain that I made "loops" with around each of the exhaust manifolds. I used the transmission jack to support the transmission pan as we slide the engine and trans out together. Once I had enough clearance, I threw a ratchet strap around the transmission (between the back of the pan and 4wd extension) and connected that the main eye hook on the cherry picker. I took out the slack as space made it available, which helps "lift" the rear of the transmission. This made clearing the crossmember at the front of the frame much easier.

[Leo helping me slide the engine back and I work the ratchet strap]

What to save vs throw out
Item's you'll 100% want to save:

• EVAP Purge solenoid (near your battery box)
• EVAP Purge hoses
• A/C compressor
• A/C lines
• Fuel Lines
• t-case to trans nuts

The rule of thumb her is to save everything until you know otherwise. That said, I've already purged a few items I know I'll not be reusing, like the OEM airbox, air tube, etc.

Things to Photograph / Label
Honestly there isn't a whole lot of stuff you're going to reuse and when things go back together, it should seem fairly intuitive. That said, a few small zip-lock bags and a Sharpie is always a good idea.

 

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Frame & Engine Bay Prep
Motor mounts
There are many companies that make new frame mounts to facilitate Hemi or LS swaps. JSS offers both weld-on style mounts and "bolt-on mounts". The former requires you to cut off your OEM 3.8L frame mounts, while the latter allows you to keep your OEM frame mounts in place. Both are good options, though the "bolt-on" mounts come at a much higher cost ($295 vs. $750) and make an even tighter engine bay even more so. They also require you to shave some accessory bolts down (e.g., the hold down for the oil dipstick, and the knock sensor mounting bolt), and they also make replacing the knock sensor impossible with the engine in place (not that OEM knock sensors go bad all that often). Not only that, the bolt-on mounts also limit what exhaust manifold/header options you have available to you.

I'm going with the weld-in mounts for my swap to keep things simple and have better overall clearances. Check out how I removed the old mounts later in this thread, post #23: Frame Prep: Removing the 3.8L Engine Frame Mounts

Steering shaft relocation & clearance

Exhaust prep

Crossmember mods

Skid plates

Heat shielding

Paint/anti-rust work

 

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Engine Prep (5.7 Hemi)
Refresh items
You have a few options when it comes to sourcing an engine. Depending on where you live, you can easily source a take-out engine, and if you look around, likely a complete take-out engine + trans (ideally from a Ram 1500 with an 8HP70 if you're looking to go that route).

You can also buy new crate motors. Although Mopar stopped making them a while ago, they're still in stock at nearly every Mopar online retailer. Perhaps now that Stellantis is offering the Hemi in trucks and cars again, perhaps we will see them making crate engine offerings again (please!!!). They not only have 345 (5.7L) crate engines, but also 6.4L, and 6.2L supercharged options. All crate engine options are LX-based, meaning they will need some changes made to them in order to fit into a JKU (see below).

My Crate Hemi is rated for 383hp/417tq. You'll note that this is slightly less HP than the Ram Truck 5.7L (395hp) and slightly more torque (410 ft-lbs), which is often credited to the differences in the intake. The Ram 5.7's have a taller intake with "SRV" (Short Runner Valve), which changes the length of the intake manifold's runners. It uses longer runners at lower RPMs for better torque and shorter runners at higher RPMs for better horsepower. Remember that these are "peak" numbers and the engines are programmed a bit differently. Some say that the power characteristics of an LX engine (car/SUV) are better for a Wrangler, but I would seriously doubt anyone would notice in a side-by-side comparison.

[My 345 Mopar Performance Crate Motor, with torn apart 2010 VVT block and cylinder heads in the background on the floor]

If you happen to get a low-mile donor, you may not need to do anything. However, there are some known hemi issues that may be worthwhile to address now. The biggest issue plaguing Hemis, especially ones that have counterintuitively been driven softly or allowed to idle for long amounts of time, is the issue with the cams getting chewed up by failed lifters.

[Chewed cam lobe, third from left]

This very issue happened to the donor engine I originally purchased. What generally happens is that oil pressure is low, either due to poor maintenance, excessive idling, long, sustained stretched of low oil pressure (like say cruising for hours upon hours in hot weather with the engine only turning 1300-1600 rpm), and any combination of the three. When oil pressure is low, the needle bearings inside the rollers of the lifters get starved or clogged/gummed up. Once they do that, they stop spinning. As the cam now acts like a flat-tappet cam, you get the infamous "Hemi tick".

The constant beating of the lobe loosens and eventually destroys the needle bearings inside the roller, causing it to eventually get pushed back into the lifter body. Once there is no longer a place for the roller to move, the roller gets worn down, wearing not only the roller itself, but also the came lobe. If you catch the tick early, you can usually just swap the cam out for a new one, change the lifters, and you're good to go (most people also swap in a new oil pump and timing chain as well).

Some people take it a step further and completely eliminate the Multi-Displacement System (MDS). The MDS is what Chrysler uses to deactivate some of the cylinders of your engine, effectively turning your V8 into a 4-cylinder, saving fuel when cruising at steady speeds. Having driven in many Hemi Ram 1500's, I can confirm that the fuel savings are indeed there with MDS activated. On a drive from Houston to Phoenix one time, I averaged ~22 mpg with the A/C blasting the entire time, all while driving 80 mph across I-10.

While it's not 100% certain, it does appear that MDS equipped vehicles do experience lifter failure more often than non-MDS vehicles. Many companies, including Melling, make a "MDS Delete" kit, which includes all the parts you need to remove the MDS components from your vehicle. Note that the MDS delete will require reprogramming of your ECM (which in the case of most swaps, is automatically done).

With the exception of a catastrophic failure, the Hemi engines wear very well. In the block above, even with the chewed up cam lobe, the cam bearings looked absolutely fine, and the cylinder walls still have the factory cross-hatching on it. If you find a block with a good cam, you can generally feel safe doing the MDS delete and installing a fresh set of gaskets, knowing that doing so will provide you with reliable service life.

Oil Pans
Truck engines are rear-sump; LX platforms are front/center sump. You'll need a rear sump pan, plus the corresponding pick up tube and windage tray.

The easiest option is to buy the Mopar Performance Rear Sump Kit, PN 77072450AB. However, these are getting harder to find (though with the reintroduction of the Hemi by Stellantis, this may get easier soon!)

Here are the PNs for individual parts, all of which are easily sourced at your local Mopar dealer or online.

Part Description	Mopar P/N:
Oil pan pick-up	53021522BD
Oil pan pick up bolt with stud	6506333AA
Oil pickup tube nut	6502756
Engine Oil dipstick	53021858AD
Engine Oil dipstick tube	53021322AF
Engine Oil dipstick tube O-ring	53021144AA
Main bearing cap bolt	6506272AA
Oil Pan windage tray	53021568AE
Oil Pan, 5.7L Truck Oil pan	53021334AF
Oil Pan Bolts	6508065AA
Oil Pan studs	6508066AA

Flexplate
Depending on what you get your donor from, and what transmission you're going with, you may need to change your flex plate out.

[LEFT: 2010 VVT 5.7L w/545RFE flex plate; RIGHT: New Mopar flex plate with new backing plate]

The flex plate and backing plate is compatible with all V6 and V8 NAG1 and 8HP70/75 transmissions. You can reuse your original flex plate mounting bolts, just make sure to clean them and use some fresh Blue Loctite.

Part Description	Mopar P/N:	Qty​	Notes:
Flex plate (NAG1 & 8-speed)	4752574AB	1​
Flex plate Backing Plate	4736613AA	1​
Trans TC to Flex plate Bolts	6509361AA	6​
Flex plate to Crank Bolts	6503465	8​	70 ft-lbs
Transmission Crank Pilot Sleeve	4736283AA	1​	Needed on pre-2017 transmissions with small diameter torque converter snout

Installation is easy - the flex plate can only mount one way due to the offset of the mounting bolts. Use fresh blue Loctite and torque to 70 ft-lbs. Note that my crank still has a pilot bearing inside, because the crate motor originally came fully dressed with a Mopar Performance Clutch meant for manual trans use. I'll pick up a rental pilot bearing puller this afternoon and get this removed so I can finally get it mounted on my engine stand.

Engine Crank Sleeve
I did not see this mentioned anywhere in the JSS YouTube videos or in Todd's BOM documents, but JKB Off-road mentioned something of note in his Episode 5 of his JKU Hemi swap series. It looks like for pre-2017 (and perhaps some early 2017) Ram 1500's came with an 8HP70 transmission that has a small "snout" on the end of the torque converter.

[Screen shot from JKB Off-road Episode #5 video showing the size of the "small" snout on his 8HP70]

If you have a transmission with a snout this size, you'll need Mopar 4736283AA Sleeve-Crank Shaft Pilot:

However, from ~2017 and up, the Ram 1500 8HP70/75 transmissions came with torque converters that had a larger snout:

Which matches the size of the crank pilot hole perfectly and negates the need to use the sleeve.

 

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T-Case & Transmission Prep (8HP70)

T-Case Selection
If you intend to run the 8-speed, you will need a t-case from either a 2007-11 Jeep JK with Auto Trans or a 2007-18 Jeep JK with Manual Trans. If you have a 2012-2018 JK with Auto Trans, you'll simply need to source a used t-case from a manual trans or an earlier year.

You can run a Sport case (2.72:1 ratio) or a Rubi case (4:1 ratio). However, many of the people that have decided to run a Rubi case behind a Hemi + 8HP70 wish that they went with a Sport case. Some of the people I've talked to have even decided to switch to a Sport case after going with a Rubi case. Why? Well it comes down to gearing.

The 8HP70 has a great gear spread:

• 1st Gear: ~4.714
• 2nd Gear: ~3.143
• 3rd Gear: ~2.106
• 4th Gear: ~1.667
• 5th Gear: ~1.285
• 6th Gear: 1.000 (Direct)
• 7th Gear: ~0.839
• 8th Gear: ~0.667 (Overdrive)
• Reverse: ~3.317

If you've got 5.13's gears and a Sport Case, you'll have the following crawl ratio: 4.714 x 2.72 x 5.13 = ~66:1. Unlike with a manual transmission, you'll get additional torque multiplication of ~1.8x, bringing your 66:1 to 118:1. This is well over the "golden target" of 100:1 crawl ratio that many manual transmission owners shoot for. Now, if you had a Rubi case, you'll have a crawl ratio of ~97:1 (at idle). If you're on the throttle off a stop, you'll get that extra multiplication until your converter hits it stall speed, pushing you up to ~175:1. This is a crazy crawl ratio and with even a bone stock 5.7L, you'll likely be pushing through your brakes constantly.

Cooler Line Rework
TBD

Shifter Conversion
TBD

TCM Updating
TBD

 

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Engine & Transmission Installation

• Mounting
• Best order of operations
• Torque notes
• Clearance checks
• Things to test before final tightening
• Driveshaft details

 

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Wiring, CANBUS, & Electronics

• CANBUS integration
• PCM choice & placement
• Hemi ECU programming
• JK TIPM compatibility
• OBD2 retention
• Sensor solutions
• Radiator fans + controls

 

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Cooling, Fuel, Exhaust Systems

• Radiator & hoses
• Fan systems
• Fuel pump & line conversions
• Exhaust manifolds/headers
• Y-pipe and O₂ sensor placement

 

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FEAD & Accessories (PS, AC, Alternator, Intake)

Mopar refers to the accessories at the front of the engine as the "Front End Accessory Drive" (FEAD). You will often see this in Mopar materials, especially on stuff that isn't vehicle specific and is intended for use on their crate engines. Accessory fitment for VVT engines is generally a result of getting the correct "length", which can be broken up into three main types:

1. VVT Truck Length*
2. VVT LX "Short" Length (often referenced as "09-10 Grand Cherokee")
3. VVT LX "Long" Length (2011+ Cars and SUVs), this is sometimes referred to as the "LD" length (explained below)

Some history that helps explain the differences:

• The "LX" moniker is used ubiquitously across Hemi swap pages and info, including here. As you do your research into things, keep in mind that people use "LX" because this was the original Mopar platform designation that was applied to the early cars that replaced the LH platform (front wheel drive). The original "LX" cars include the Chrysler 300, Magnum, and early Chargers, generally from 2005 to 2010. For the 2011 model year, the Charger was updated and given the "LD" platform code.
• All Hemi engines, regardless of platform, went to the VVT style in 2009. This engine update was not coupled with any platform change, which means that original LX platform cars like the Charger could be non-VVT or VVT. People however still referred to the engines from cars as "LX", adding "VVT" to help differentiate the two.
• The Challenger, which is officially designated as the "LC" (2008-2014) or "LA" (2015+) is still referred to as having an "LX" motor. Note that all 2008 Challengers were equipped with the 6.1L, so any 5.7L from a Challenger will be a 2009+ VVT.
• Just like with the cars, the Hemis in the Ram trucks went VVT in 2009+ model years. This means that non-VVT accessories won't fit VVT engines. *Additionally, just like the with the LX platform update, Ram engines underwent a major change in 2011, and generally 2011+ accessories will not interchange with 2009-2010 timing covers.

Some things to keep in mind with the above info:

• Accessories are not swappable between LX and truck styles without changing the timing cover and ALL accessories.
• Between the two different LX lengths, the timing cover is the same but accessories and crank pulley are different, making the accessory drive 1" shorter than 2011+ accessory drives.
• All 2013+ Hemi car engines came without a belt-driven power steering pump.
• 2011+ 5.7L and 6.4L front end accessory drives are all the same (car or SUV)

Todd from JSS has a good video here:

In my email discussions with Todd, he says that in the early days like 2005-2010, it was common to just use the "early" style accessory drive ("LX short"). Then, in 2011 the new LX engine came out with a slightly longer front drive (+1 inch). At that point, they (JSS) started using the 2012 Challenger accessories because it has a belt driven power steering pump and a P/S pulley that fits a lot of swap uses.

Alternator
My crate engine is based on a 2015+ Dodge Challenger block and internals. This means that nearly any alternator from that era will fit. Additionally, earlier WK (Grand Cherokee) and other 5.7L SUV alternators will fit, though they mount with "ears" similar to older style alternators. Newer alternators have mounting blocks (similar to your A/C compressor) and generally fit just by bolting in place. Older style "ear" alternators may or may not need one of the mounting bosses drilled out to accommodate the mounting bolt (the bolt goes through the timing cover and into the block for support).

Todd from JSS told me to use "2012+ Challenger accessories", including the alternator. There are lots of output offerings from that era. The base R/T Challenger comes with a 160 amp alternator, though the 180 amp alternator appears to be the most commonly installed version on factory vehicles. As I started looking for OEM Mopar options for my engine, I found that Mopar offers the correct 180 amp alternator as part of their "FEAD Basic Kit", which comes with a bunch of other items I need (idlers and belt tensioner, plus the mounting hardware). The best part - the FEAD "kit" was only $567 shipped to my door. This was about $40 cheaper than the new Mopar 04801833 alternator by itself. Throw in the fact that this includes the hardware, idlers, and tensioner, the cost savings in nearly $250! Not that any Hemi swap is "budget friendly", but saving $250 is always nice...

Power steering
You cannot run a truck power steering pump b/c the pump pressures are too high for the OEM steering gear. However, if you're going to use hydro-assist or a PSC box, you may be able to make it work. Check out Todd's BOM for more information specifically for what needs to be done for fitment of a Truck VVT Hemi and PSC boxes.

A lot of people have made the Grand Cherokee pump and reservoir work, as these seem to have better working pressures for the OEM Jeep Steering Box. This of course requires GC "short" engine front accessories, or spacers.

If you want to see how I made a PSC "Hemi Kit" work on my crate engine, see that here: https://wranglerjkforum.net/threads/jku-hemi-swap-reference-guide-swap-info.32731/post-471745 and here: https://wranglerjkforum.net/threads/jku-hemi-swap-reference-guide-swap-info.32731/post-471796

AC system (a big one!)
Depending on your swap choice, you may be able to use your OEM 3.8L compressor. You can find a more detailed post here: https://wranglerjkforum.net/threads/jku-hemi-swap-reference-guide-swap-info.32731/post-471797

Belt routing
Your belt routing will depend on your engine type, which can be confusing depending on minor differences in year changes. Pay attention if you get a take-out engine and take a photo before you start taking things apart to refresh.

Intake Manifolds
Generally speaking, the LX engines, 5.7L or 6.4L, will all take the same FEAD parts. Truck 5.7L and many truck 6.4L FEAD items will interchange. The main difference between the LX and VVT Truck accessories comes down to the difference in the timing cover, which itself is different to support the difference in intake manifold designs. If you're at a junkyard or swamp meet, the easiest way to tell a Truck 5.7L apart from a LX 5.7L is to look at the intake manifold:

[2010 Truck 5.7L VVT; the throttle body faces up towards where the hood would be]

As you can easily see above, the intake on the truck engines has a throttle body that points "up". All LX (car/SUV) intakes face forward:

[LX based motor intake and throttle body - faces towards the front of the engine]

Airbox solutions
Your OEM airbox wont work. There are some OEM options, including air tubes that will work, though JSS offers an airbox replacement that uses a Mopar Performance or similar "cone" style filter.

 

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First Start, Tuning, Troubleshooting

• First-start checklist
• Common Hemi swap codes
• Idle control issues
• Gear ratio tuning
• Transmission behavior
• How the Jeep behaves with current gearing, tire size, and the 8HP70

 

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Driving Impressions & Performance Notes

• How it drives vs the 3.8
• Temps under load
• How the 8HP shifts
• If the gearing feels right

 

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Final Wrap-Up

Drivability
TBD

What I'd do differently
TBD

Thanks to vendors/sources
TBD

Total Cost
We've all seen posts on forums and Facebook where someone claims that their best friend's, neighbor's, daughter's boyfriend's dad did a Hemi/LS for $2500 and a case of Natty Ice. These same folks are often the same ones saying that they built a set of Super Duty axles for $1500 and have been beating on them in Johnson Valley with 42" stickies for 2 years and never had any issues.

Sure thing pal...

I've called bullshit on those posts for years. In the near decade that I've been keeping track of these things, I've only ever seen two people provide full build sheets with all costs listed out, and both of which were right around the $10,000 mark (both of which got new transmissions too). For a VVT Hemi swap, like anything really, much will depend on your ability to do the work yourself. If you're able to weld, are comfortable doing major changes to things, and have the necessary tools and equipment (or are willing to buy or borrow), you'll probably be around $12-15k.

My total at the moment is $14,495, though part of that total includes a ~$500 estimate on miscellaneous items such as transmission fluid, engine oil, hardware, hoses, etc. (I will update the table below as needed). I admit that my swap is on the higher side - the crate engine for example was probably 2-3x what you can find a good junkyard/recycler engine for (if those are available in your area). Remember from my build page though that I already got a Ram 1500 5.7L take-out (and the guy sent me a video of the engine starting and running!!) and it STILL had a chewed up cam. I bought four new O2 sensors b/c the ones from my 3.8L had 209,000+ miles on them - your mileage may vary on that expense. I also have nearly $800 into a PSC pump and mount setup to support my PSC box and hydro-assist. You may be able to get by perfectly fine with an OEM option...

There is one major area where you could cut and shave some $$ - the transmission. If you had a NAG1 equipped JKU and just wanted to replace a sellable engine and had an otherwise good transmission, you could conceivably come in ~$8000 if you were able to source a cheap take-out Hemi with low (ish) miles that is ready to bolt into place.

Still, no matter how you slice it, any V8 swap is pricey. If I lived out west still, I would for certain be keeping an eye out for one of the many, many Hemi-swapped builds that I see come up in my feed for sale (though admittedly, I like the "build" itself). Don't forget about the ancillary parts too that I'm not listing here. For example, the driveshafts. I'm already needing a set of driveshafts to accommodate the 1-ton swap, but you'll probably need to adjust driveshaft lengths to account for the different driveline dimensions.

Speaking of driveline, are you going to run a ~400hp+ V8 on stock axles? I don't doubt the D44 could hold up to "reasonable" use, but who the hell wants that when you just installed a V8? Same for a front D30, and especially so with larger tires. Things will escalate quickly - so be prepared for it...

 

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Long-Term Lessons Learned + Things to Consider

• Expanding on any of the above items after some time
• Long term changed desired

 

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Future Updates

• If I change anything, e.g. go with a Hellcrate, I'll post it here as well as the necessary information.

 

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Reference List

• https://jeepspeedshop.com/shop/
• https://www.holley.com/blog/post/everything_you_wanted_to_know_about_gen_iii_hemi_engines/
• https://www.dodgegarage.com/news/ar...iii-hemi-engine-quick-reference-guide-part-iv

 

[pc1p]

Pilot Bushing & Bearing Removal
You may or may not have to deal with this, but thought I'd include some tips for what apparently is a common issue getting these bushings and bearings out of Gen III Hemis.

Many of the 345 Hemi Crate engines come "fully dressed" - full of oil, exhaust manifolds, spark plugs, and clutch pack factory installed and ready to go. As you can see above, mine was no exception. The pilot bearing, OEM# FC69907, is actually sold and installed as a bearing (red arrow) and bushing (green arrow) combo. While this makes installation easy, it came make removal a pain in the a$$...

What inevitably happens is the bearing will pop out independent of the bushing around it. The issue that you'll face now is that the bushing itself does not have an accessible lip that would allow you to use a pilot bushing/bearing remover to grip on to. There are a number of ways to fix this. Some people use the old bread or grease trick, which can be effective, albeit messy. For me, I simply went with the "when in doubt, weld it out" approach.

A few tack welds around the edge of a nut that your slide hammer fits into...

...followed by a few whacks of the slide hammer and it pops out without any issues.

Something to be mindful of here - make sure you prep and plan for spatter. I cleaned things up well, and lowered my gas flow just a hair to keep spatter from blowing into the crank end. I had a few small balls land on the edge, but nothing I couldn't remove with a small screwdriver and polish away with an emery cloth. If you're using a flux-core welder, you may want to be diligent with some spatter shield before doing this.

Now that the flex plate is installed and pilot bushing removed, I was finally able to get the motor on the stand and off the pallet! As you can tell by the mess in the back of the garage, I need to finish organizing some stuff and taking some things to the trash (like the pallet this came on!). Cluttered workplaces are not enjoyable...

 

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Decided to buy myself an early Christmas gift… I’ll post how well it works as I go through the rest of the swap:

 

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Like an idiot klutz caveman normal dude excited to get working on a V8 swap, I broke the terribly placed vacuum nipple at the back of the intake manifold at some point last week. I looked back there and it was dangling…

I decided to try and fix it with some mechanical support and plastic weld. I used some 3/16” brass tube and some 2-part plastic weld epoxy, and it seems to be as good as new. Actually, it may be slightly better now that the nipple will never break again…

I used a brake flare kit to put a small flare on the end to prevent the brass from getting sucked into the intake manifold.

I got this at Hobby Lobby in the craft/model car section…

I used a dowel rod and plastic clip remover to keep pressure on the tip as the epoxy was curing.

Good as new!!! I used the epoxy inside to secure the brass tube to the plastic nipple, as well as the intake hole, and then used the same epoxy to weld the pieces together for a good seal.