Swap a Modern HEMI Into Your Classic Mopar with Mopar’s New Crate HEMI Engine Kits


The Dodge Shakedown Challenger, a blend of design cues from the past and present, features a new Mopar 392 Crate HEMI® Engine Kit under the hood to help administer a 6.4-liter HEMI® jolt to the heart of the classic 1971 Challenger.

With modern HEMI swaps into old Mopars becoming quite popular, Mopar has decided to step up their game with a fantastic announcement at the 2016 SEMA (Specialty Equipment Market Association) show in Las Vegas! For those that have installed or are in the process of installing a modern HEMI engine into your classic Mopar, you know how tough it can be getting all the electronics and computer systems to work properly. After all, you are trying to run them in a car they were never designed for.

Mopar has just announced a complete game changer for modern HEMI swaps with their new Mopar Crate HEMI Engine Kits that provide enthusiasts with a factory-backed, budget oriented plug and play option for putting Gen III HEMI engines into 1960’s and 1970’s Mopar vehicles. Their awesome all-new Mopar 345 Crate HEMI Engine Kit for the 5.7L HEMI engine and Mopar 392 Crate HEMI Engine Kit for the 6.4L HEMI can be paired with all 1975 and older Mopar vehicles! Each kit includes a power distribution center, a powertrain control module (PCM), engine and chassis wiring harnesses, an accelerator pedal, O2 sensors, ground jumper, charge air temperature sensor and in-depth information sheets on installation.

The Mopar 345 Crate HEMI® Engine Kit for the 5.7-liter engine a

A factory calibration is loaded on the unlocked PCM and bumps the horsepower to 383 and torque to 425 lb.ft. for the 5.7L HEMI engine, while staying around the same for the 6.4L HEMI at 485 horsepower and 472 lb.ft. of torque. Mopar’s Crate HEMI Engine Kits are designed and optimized for use with manual transmissions although automatic transmissions such as the Torqueflite 727 and 904, while not optimal, can also be adapted for use. The kits can be used with a previously purchased new or used 2014 or newer 5.7L or 6.4L HEMI engine, or customers can purchase a new 5.7L or 6.4L brand new crate engine with the Crate HEMI Engine Kit together. These kits feature a Mopar two-year/unlimited mileage warranty. To better aid with the install, Mopar has also gathered together additional engine accessory hardware components enthusiasts will need to suit their individual installation needs including a power steering expansion kit, AC expansion kit and rear sump oil pan kit.

“Our new Mopar Crate HEMI Engine Kits answer enthusiast demand for a relatively simple solution for plugging modern-day HEMI engine power into their classic Mopar rides,” said Pietro Gorlier, Head of Parts and Service (Mopar), FCA – Global. “The engine kits include the hardware to plant a 5.7-liter or 6.4-liter HEMI engine under the hood with the factory-backed confidence that comes when using Mopar parts. They also offer optional front-end accessory kits like power steering or even exhaust manifolds to make installation easier. Starting today, our fans can order the kit online and start working on their favorite project with the peace of mind that comes when using a Mopar product.”

Both Mopar engine kits have a MSRP of $1,795 each and are available for purchase now through your local Chrysler/Dodge/Jeep/Ram dealer either in-store or online at www.Mopar.com/CrateHEMI.
Part Number/Manufacturer’s Suggested Retail Price (MSRP) Information:

Mopar Crate HEMI Engine Kits
345 Crate HEMI Engine Kit (PN 77072455AC): For use with 5.7-liter engine assemblies; power distribution center, powertrain control module, engine and chassis wiring harnesses, accelerator pedal, O2 sensors, ground jumper, charge air temp sensor, in-depth installation information sheets MSRP $1,795

392 Crate HEMI Engine Kit (PN 77072454AC): For use with 6.4-liter engine assemblies; power distribution center, powertrain control module, engine and chassis wiring harnesses, accelerator pedal, O2 sensors, ground jumper, charge air temp sensor, in-depth installation information sheets MSRP $1,795

Engine Assemblies
5.7-liter Gen III HEMI Engine (PN 68303088AA): Requires 345 Crate HEMI Kit MSRP $6,070
6.4-liter Gen III HEMI Engine (PN 68303090AA): Requires 392 Crate HEMI Kit MSRP $9,335

Engine Accessory Hardware Kits (for 5.7L and 6.4L engine assemblies)
Car FEAD Basics Kit (PN 77072445): Alternator, belt, pulleys, bolt MSRP $625
Car Power Steering Expansion Kit (PN 77072448): Power steering pump, belt, bolts MSRP $255
Car AC Expansion Kit (PN 77072446): AC compressor, belt, bolts MSRP $350
Rear Sump Oil Pan Kit (PN 77072450): Oil pan, pick up tube, gasket, bolts MSRP $179
45 Degree Oil Filter Adapter (PN 77072447): Filter adapter, oil filter, bolts, seal MSRP $89
Jeep SRT Exhaust Manifolds (PN 77072462): Manifolds, gaskets, bolts MSRP $349

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Cody Krueger

Cody Krueger

Car Feature Editor – cody.cole@shawgroupmedia.com Since the age of 4, Cody has been obsessed with everything Mopar. On Christmas of 1998, Cody's parents gave him a rusty '69 Charger shell that his father saved from a field. Cody's garage still features that '69 Charger as well as the additions of a '70 Coronet, '71 Charger R/T, '71 Road Runner, '04 SRT-4, '06 Grand Cherokee SRT8, '08 Challenger SRT8 and a '17 Ram 1500 Rebel. Cody can truly and proudly say him and his wife are true Mopar nuts in love with all types of Mopars!

72 comments

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  1. Avatar
    Sam 16 June, 2018 at 17:20 Reply

    Will these crate engine kits work in a 1987 Ramcharger?

    I know the article says 1975 and later.

    Just would like to drop one in

  2. Avatar
    Arthur Schneider 19 July, 2018 at 12:54 Reply

    Will a 6.4 Liter drop into a 1948 Desoto Custom? What transmission would you recommend? Thank you.

    • Kevin Shaw
      Kevin Shaw 20 July, 2018 at 09:23 Reply

      That’s a tough one, Arthur. Thankfully, the bellhousing bolts will fit all LA small block transmissions, so you can snug up a 904, 727, 4-speed or a modern Tremec. There’s also Silver Sport Transmissions’ A41 overdrive automatic too.

  3. Avatar
    marcos 1 August, 2018 at 21:21 Reply

    would this me able to be put into a 1980 jeep wagoneer? what all would i need as far as parts? motor mounts?

  4. Avatar
    Larry 11 August, 2018 at 04:12 Reply

    Looking to upgrade my 1967 Barracuda convertible from it’s current 225/6 904 automatic and 7.25 rear end to a 6.4 setup. Can I use the existing transmission and gears with the new block? If so, will it just bolt up to the current transmission, or would that require modifications?

    • Kevin Shaw
      Kevin Shaw 12 August, 2018 at 22:24 Reply

      The modern 5.7, 6.1, 6.2 and 6.4 engines have a bellhousing pattern similar to a small block/LA motor. Unfortunately, it is very likely that your new 6.4 is simply far too powerful for your current stock setup.

  5. Avatar
    tim s 1 September, 2018 at 20:44 Reply

    My 1970 Plymouth Cuda came stock with 383, would this setup work? I also want to use modern transmission, any recommendations to pair a modern Hemi and transmission to fit in engine bay of the 70 Cuda?

    • Kevin Shaw
      Kevin Shaw 2 September, 2018 at 19:50 Reply

      There’s a LOT that goes into dropping an late model EFI engine into a classic car. Getting the new 8-speed TorqueFlite is also a HUGE endeavor that custom shops are struggling to figure out. There’s quite a bit of floor cutting to get that new tranny in too.

    • Kevin Shaw
      Kevin Shaw 13 March, 2019 at 20:39 Reply

      Seeing that the bell housing bolt pattern is that of a 904, I strongly suggest either an American Powertrain or Silver Sport Transmissions 5-speed manual transmission kit.

  6. Avatar
    Ronald Schally 17 March, 2019 at 18:59 Reply

    I have a 1970 Dodge Charger that has a 440 and 8 3/4 rear end. I would like to Put in a 392 Hemi and keep the beefed up 727 to avoid floor cutting. Is the 727 with 2500 rpm stall, shift kit, and extra clutches OK? Does the 392 require cutting out any any other parts of body ?
    Thanks

    • Kevin Shaw
      Kevin Shaw 18 March, 2019 at 07:06 Reply

      The problem is that the 727 bellhousing bolt pattern DOES NOT line up with the new 6.4L Hemi. A 904 does, but not the larger 727. There are adapter plates, but they’re thick and throw off the conversion engine mounts and/or the transmission cross member. The long answer is that it’s gonna be a HUGE pain in the butt.

  7. Avatar
    mark 19 March, 2019 at 11:01 Reply

    Hi
    I am the proud owner of a 1968 dodge sweptline crewcab. I just picked up a 2017 ram 5.7 with 8 speed trans and transfer case. so my obvious question is how or where do i get this kit.

    • Kevin Shaw
      Kevin Shaw 24 March, 2019 at 19:38 Reply

      Understand that the bellhousing bolt pattern is identical to a 904, so your choices are limited. If you’re looking at a manual 5- or 6-speed, your choices are American Powertrain or Silver Sport Transmissions (the latter is designed with a factory center console).

      For automatic, Silver Sport Transmissions offers their A41 4-speed overdrive with an adaptive bellhousing.

  8. Avatar
    dennis servis 3 May, 2019 at 10:01 Reply

    we have a 1971 duster and will be putting in a2015 hell cat 6.2 sc with it automatic transmission any one done one need front end info for motor mounts can front end be brought or better to build one

    • Kevin Shaw
      Kevin Shaw 3 May, 2019 at 10:04 Reply

      You’re not going to want to run that 8spd. auto. You’ll hamstring yourself with electronics and frankly, will have to gut your floorpan and crossmembers.

  9. Avatar
    Ron Langevin 20 May, 2019 at 14:11 Reply

    I am doing a rotiss resto on a 71 Challenger. It was a S. D. Car and no salt rust but sat in tall grass a while. Got all the replacements welded in and purchased a used 2006 Charger 5.7 with a 5 speed auto. And everything associated with the engine. Car was in a easy rollover. The seller started car, removed everything, wiring, all harnessing, 12” of the 3 In. Exhaust tubing so all sensors are on exhaust. The electronic gas pedal, shifter, all accessories are there. Looks like all I need to replace is serpentine belt. Of the listed parts, I think I need the chip that isolates the engine only as i hope to use the cars wiring. Is this possible and if so what and where Do I buy it. Also where is the books listed that you say are available. Appreciate if you could email answer or message me. 1stealthcar@gmail.com, Ron Langevin.

  10. Avatar
    Peter Huizing 26 June, 2019 at 01:01 Reply

    Hello Kevin,
    I own a Dodge Ram 1500 Laramie with a 5.7 hemi. I want to swap it with a hemi from 2010. Is there anything to I have to need to change or is it one easy job?

    Best regards Peter Huizing

    • Kevin Shaw
      Kevin Shaw 26 June, 2019 at 09:13 Reply

      Physically, it shouldn’t be a problem swapping the engine itself. What you’re going to encounter is MAJOR engine management issues. The FCA hardware isn’t going to “play nice” with your truck’s existing hardware. The software won’t jive either. You’re better off just upgrading your existing 5.7L Hemi with a tune, exhaust, and other performance parts.

    • Kevin Shaw
      Kevin Shaw 26 June, 2019 at 09:14 Reply

      It’s going to be a nightmare. Especially when it comes to computer management hardware and software. Your older Ram will not communicate with the new FCA engine management software.

  11. Avatar
    Joe 27 June, 2019 at 10:50 Reply

    I am thinking of putting in the Mopar 392 Crate HEMI Engine in my 1968 Charger. Can this be done for under $100,000?
    Thanks. Joe

    • Kevin Shaw
      Kevin Shaw 28 June, 2019 at 10:21 Reply

      Oh goodness, yes! Both Holley and Edelbrock sell standalone wiring harnesses, as well as Mopar itself (although not a classic/modern swap-friendly).

      The G3 Hemis have a small block (LA) bellhousing pattern, so note that you’ll want to consider beefing up a 727 TorqueFlite or manual trans (or swap to a modern 5 or 6 speed Tremec through Silver Sport Transmissions).

      The hard part is that the G3 Hemi requires far more voltage than the factory wiring harness can handle. The ECU, EFI and engine management sensors require 14amps at all times. This means you’re going to need to replace much of your Charger’s wiring.

  12. Avatar
    Mike 30 June, 2019 at 15:53 Reply

    I’m seriously considering replacing the 440 in my 65 Satellite with a 5.7 Mopar crate engine. I would prefer to retain the 727 and install a Gear Vendors unit behind it. What if any suspension modifications will be necessary front and rear. I am needing to replace my steering box with a new Borgeson unit regardless of the engine swap but want to budget wisely for the ultimate Gen III swap. I am anticipating that I will need to completely update all of the original wiring to work with the modern electronics for the new drivetrain. Any suggestions and recommendations you can give me to help make this project as efficient and cost effective is greatly appreciated

    • Kevin Shaw
      Kevin Shaw 30 June, 2019 at 19:17 Reply

      Mike, you’ve got bigger problems than just suspension. The ugly little secret that NOBODY talks about is the need to completely rewire your car to handle the necessary constant 14V needed to operate a new 5.7L Hemi. The electrical system in a classic Mopar (until the mid 1970s) was the weakest link, and the strain on the factory harness will likely cause a domino effect of failures that will having you hating yourself and your car for years.

      Of course, your radiator, fan(s) and transmission cooler will not work either as the coolant hoses are in different locations. Holley has a new series of aluminum “Frostbite” radiators that are made in the US which I like. You’ll want to give them a call.

      Now, if you’re ready to extract ALL of the factory harness with a Painless or American Auto Wire kit, change to a one-wire alternator (thus losing use of your factory ammeter), then we can proceed.

      G3 Hemi swaps don’t require changing the steering or suspension whatsoever. Motor mount kits are available through Schumacher and Mancini Racing. Obviously, your headers/exhaust will need to be changed as well.

      The G3 Hemi bellhousing accepts all SMALL BLOCK bellhousings. A Chrysler 904 or TorqueFlite 727 (again, for a small block) will work, as will your Gear Vendor. This means that NO! your big block 727 will not mate to it.

      Sell the transmission you’ve got, source out a small block TorqueFlite and have it built to spec.

      The G3 Hemi weighs quite a bit less than your 440, as will the smaller transmission, so you’ll immediately feel the difference in your Belvedere’s power-to-weight ratio. But unless your 440 is a lazy dog, you’re looking at quite a drop in horsepower.

      • Avatar
        Mike Rodriguez 1 July, 2019 at 12:11 Reply

        Kev in,

        Thanks for the prompt response. My car was an original 318, automatic car and the 440 in it now is no slouch. I am really looking for drivability and reliability as I am hoping to make the car my mostly daily driver and have it perform similarly to the 2006 Charger Daytona I regrettably sold. I can easily change the existing Edelbrock carb to a FI-Tech EFI setup and then just add the GV to get the overdrive gearing. Either way I am expecting to completely upgrade the car’s electrical system because it is definitely the weak point that keeps me from driving the car more than I would like. It sounds like I would need to go with a 6.1 or 6.4 Gen III if I decide to go ahead with the swap.

        Thanks again,

        Mike

        • Kevin Shaw
          Kevin Shaw 1 July, 2019 at 20:11 Reply

          Mike, although I’m 100% all for late model Hemi swaps, seeing that your car is a strong street machine, I would STRONGLY recommend the FAST EZ-EFI 2.0 electronic fuel injection system rather than uprooting your entire car. The EZ-EFI 2.0 not only replaces the carburetor with an 8-point EFI throttle body, but also provides a computer-controlled billet distributor and electronic ignition system. You keep your engine, trans, Gear Vendor, and wiring – but you get ALL of the driveability of a new G3 Hemi. Please read this article: https://moparconnectionmagazine.com/gallery-modernizing-your-mopar-with-the-fast-ez-efi-2-0/

  13. Avatar
    Tim 30 June, 2019 at 20:13 Reply

    I have 72 duster, other than wiring, is the 5.7 Heim swap drop in. And would a automatic or manual trans be the easy way to go

    • Kevin Shaw
      Kevin Shaw 1 July, 2019 at 08:15 Reply

      It should drop in, you’ll obviously need a set of motor mounts and a new radiator.

      The transmission is a matter of choice. Silver Sport Transmissions has a modern 5 or 6-speed manual Tremec swap. Otherwise, you’ll need to find a 904 or 727 for a LA motor.

  14. Avatar
    Brandon 14 August, 2019 at 18:23 Reply

    I’m interested in doing a III gen hemi swap on my 74 Ramcharger. I’m running a 360 now and wanting something different. any suggestions do’s and don’ts? Just looking to get a grasp if its worth my time.

    • Kevin Shaw
      Kevin Shaw 15 August, 2019 at 08:34 Reply

      Ideally, keep your LA-pattern transmission. I’m not sure about motor mounts as Schumacher only has them (to my understanding) for cars at this time. The biggest issue is electrical. Not only do you need far more juice to operate the ECM, but a mightier alternator to feed it. This means almost completely rewiring your truck. 12V ain’t gonna cut it.

  15. Avatar
    Ben Nokleby 12 September, 2019 at 23:31 Reply

    That’s the biggest thing to most guys. The wiring. Like why can I get anything for a now older gen3 but can’t get a 2014 vvt motor up and running for the same or less than I paid for the whole engine.

  16. Avatar
    Ryan 10 October, 2019 at 15:35 Reply

    Kevin,

    Just for clarity, the GenIII electronics do not run on 14 amps, it 14 volts. Voltage and current are 2 totally different things. 14 amp into those sensors would probably burn them up.

  17. Avatar
    Joe Nelson 30 December, 2019 at 22:19 Reply

    Hi Guys.. I have a 2016 392 that I want to put into my 1972 Dart “Drag Week” car. I am thinking of using a NAG-1 trans with the 8 3/4 diff. Any thoughts on this combo? Thanks in advance…

    • Kevin Shaw
      Kevin Shaw 30 December, 2019 at 22:29 Reply

      If I could say anything, it would be to convince you to NOT do the Nag-1 trans. They’re horribly problematic, you’ll completely gut your floor/cross member to get it to fit, and right now, there’s little in the way of TCM controllers.

  18. Avatar
    willie weldon` 9 February, 2020 at 13:19 Reply

    not sure if this is still open for discussion maybe someone can point me in the right direction. I am installing an 04 hemi and tranny out of a rumble bee. Into a 1974 barracuda. I have been collecting parts and working for 8 years . I bought a wiring harness from Street and Performance and unfortunately Mark Passed and the business closed down as I am told. The car goes in to limp mode as soon as you nail it I wont go in to the details and waste everyones time if I am in the wrong place. simply I used an 03 drive by wire which was mounted under the battery and they are notavailable anymore . Any suggestions on what to swap with and how to wire would be great

    • Kevin Shaw
      Kevin Shaw 9 February, 2020 at 14:52 Reply

      Willie, man you’ve got some trouble on your hands. Personally, I kinda wished you hadn’t gone with the 46RE transmission, as that typically is a source of grief. Seeing the car is running, you’re likely looking at a software issue, not a hardware one. Strongly recommend not “throwing the baby out with the bathwater” but find a qualified tuner. The best engine tuning shop who uses HP TUNER software will be your best bet. Do some searches on Google to find a HP TUNER-trained (that’s the name of the software brand) engine tuner. They’ll be able to diagnose and resolve your issue. Easy peasy lemon squeezie.

    • Kevin Shaw
      Kevin Shaw 17 February, 2020 at 14:48 Reply

      Are you asking if you can drop a new Hemi into a Crossfire? Ugh, why would you want to? That would likely take YEARS to retrofit.

      Otherwise, you’ll be very hard-pressed to find a bellhousing to adapt the two together. Just go with an American Powertrain or Silver Sport Transmissions’ bellhousing and Tremec 5 or 6-speed manual.

  19. Avatar
    Rob Thomas 6 April, 2020 at 19:14 Reply

    Hi Kevin, First I want to thank you for all of your work on this post – the info has been valuable.

    I have a 65 sport fury convertible that I would love to put a Gen III Hemi in. What engine/trans combo would you recommend? I don’t want to over do it so to speak.

    • Kevin Shaw
      Kevin Shaw 7 April, 2020 at 09:03 Reply

      First, thank you. Second, when most folks consider swapping in a new Hemi into a their classic Mopar they’re thinking “it’s gonna drive like a new car.” Unfortunately, that’s really not the engine’s doing – it’s the rest of the driveline. A modern EFI system and a hydraulic roller cam swap will smooth out your engine’s rougher edges – all while still maintaining plenty of horsepower and greatly improving driveability, ease-of-starting, and overall enjoyment. (It kinda sounds like I’m talking you out of a swap, huh?)

      A smooth shifting automatic or a nicely synchro’ed manual with a few extra gears is really the thing that makes the big difference. Lag-free shifts with zero slop can make any classic feel like a million bucks, regardless of the engine. If you’re a manual guy, go with a Tremec 5-speed swap from either Silver Sport Transmissions or American Powertrain. SST is a little more mild and designed for the guy looking to still use a factory center console, while APT is a little more geared toward the autocross/roadrace guy (not always, but in most cases).

      As for automatics, I’m a big believer is reducing – and I mean everything. Reducing the amount of wires, plumbing, linkage, cutting up the floor, etc. A TorqueFlite with a Gear Vendor gets the job done but requires manual shifting and flipping switches. (Not ideal.) A traditional 3-speed TorqueFlite just is a big ol’ pain in the butt, especially because your modern Hemi won’t graft to your classic kickdown linkage and such. A Chrysler A518 (and 46RE) is basically a TorqueFlite with an overdrive, which only recently, is beginning to get the beefier aftermarket support to make it strong enough to take some big HP. Of course, Silver Sport Transmissions has their A41 4-speed overdrive that’s electronically shifted and designed for G3 Hemi swaps too.

      I almost always try to steer folks away from trying to cram in the modern 8-speed transmission. It’s massive size requires an exorbitant amount of cutting to the floor, cross members and necessary unibody substructure. Plus, there is just sooo much wiring and electronics to find new homes for. Just avoid it like the plague.

  20. Avatar
    MW 3 June, 2020 at 13:27 Reply

    I have sourced complete running 392 8-speed Auto… with factory powertrain control module (PCM), engine wiring harnesses, an accelerator pedal, O2 sensors…will I need a complete kit upgrade, or just replace what i do not have in the picture, or who is the resident expert I need to talk to, in order to complete what I need to do? Target body 67 Barracuda Convertible, slant six car. Thanks!

    • Kevin Shaw
      Kevin Shaw 4 June, 2020 at 06:51 Reply

      Be prepared to gut the Barracuda of every scrap of factory wiring, as well as removing the transmission tunnel, cross member, torsion bar mounts and front suspension. Trying to graft in the 8-speed and all of the factory harness is 90x’s more difficult than what is being suggested in this article.

      • Avatar
        MW 4 June, 2020 at 10:02 Reply

        we already past that stage Kevin…the article was addressing the conversion kit, which is what my question was directed at. Wanna take another look at it? Thanks! >>>> will I need a complete kit upgrade, or just replace what i do not have in the picture, or who is the resident expert I need to talk to, in order to complete what I need to do?

  21. Avatar
    Fred Alexander 24 June, 2020 at 07:41 Reply

    I’m thinking about dropping a Gen 3 Hemi into one of my Plain Jane steel wheel cop cars. I have an 87 Dodge Diplomat and a 87 Plymouth Gran Fury. Is it a big deal getting the Hemi into one of those engine compartments? Also can I use the Hemis modern automatic trans or do I have to stick with the 904? Thanks!

    • Kevin Shaw
      Kevin Shaw 24 June, 2020 at 09:29 Reply

      Frankly Fred, the short answer is “don’t.” But understanding you deserve a “why” let’s begin with: Currently, I don’t know of any company making motor mounts for Diplomats, so you’ll have to make your own. Getting the engine and transmission location correct is a massive chore and requires far more math than I think you’re willing to put in. And with custom motor mounts come custom transmission mounts too. Expect to change most if not all of your cooling system, fuel system and transmission cooling as well. Speaking of which, trying to use any of the modern automatics will require the wholesale removal of your transmission tunnel and cross members, as both the NAG1 and 8-speed TorqueFlite are double the width of a 904. Next, be prepared to extract ALL wiring from your engine compartment. Currently, there are no standalone wiring harnesses that manage the engine, ignition, fuel injection AND the modern transmissions. Holley has plug-and-play standalone harnesses for engines (without the cylinder deactivation system, pre-2006) but not for both the engine and transmission – which means, you’re stuck using the factory harness and getting that to play nice with your 35-year-old harness won’t be easy. Be prepared to radically upgrade your electrical system too, because operating both control systems requires a lot of juice (14.5amps consistently). Suddenly, keeping the 904 doesn’t sound so bad, does it? So as far as analog automatic transmissions go, you can either keep the 904, bolt on a Gear Vendor overdrive, or swap out to a A41 4-speed automatic from Silver Sport Transmissions. Otherwise, just upgrade to FiTech or Holley Sniper EFI and enjoy your car all year long.

  22. Avatar
    John Mobeck 22 July, 2020 at 13:21 Reply

    Hi Kevin,

    Currently building a 69 Dodge Charger and planning to use Mopar’s 6.4L crate engine and their engine management system as well. My question is one regarding an issue I’ve seen listed in the forums……Several have mentioned that the PCM does not like the ignition switch on these old cars because they apparently don’t hold continuity in the run position while turning the switch to the crank position…..I would ask you if this is still the case with these new engine management systems, and if it is, what is your best suggestion at getting past it. I’m interested in being able to start the car without a push to start button and still make it run off the old ignition switch. Is a time delay relay the only solution?

    • Kevin Shaw
      Kevin Shaw 22 July, 2020 at 13:25 Reply

      Yes, you’re exactly right. The factory PCM doesn’t like the old ignition switch at all. The factory harness has a few other quirks not worth exploring here, but I strongly recommend you look into Holley’s standalone harness and PCM as an alternative.

  23. Avatar
    Mike Zimmerman 7 August, 2020 at 11:47 Reply

    I have an 09 Challenger that rather than trade it in I am considering doing a 5.7 swap into my 1957 Chrysler can I use the harness in the car or do I need to go this route?

    • Kevin Shaw
      Kevin Shaw 7 August, 2020 at 12:37 Reply

      No. You’re going to be rewiring the car just to support the new harness for the engine. The factory electrical system is severely ill-equipped to handle all of the voltage necessary to run the new systems.

  24. Avatar
    MICHAEL ANTINORI 8 August, 2020 at 14:31 Reply

    I HAVE A 1967 DODGE CORONET , I AM WANTING TO PUT A 5.7 HEMI WITH A 545RFE TRANSMISSION. WHAT MODIFICATIONS WILL I HAVE TO DO TO THE FLOOR PAN TO ALLOW THE TRANSMISSION TO FIT PROPERLY?

  25. Avatar
    Bob McAninch 19 September, 2020 at 09:54 Reply

    I have a 78 lil’ red express pickup with the 360. Can I mount a modern 5.7 and if possible the modern 8 speed transmission?

  26. Avatar
    Gary Jorah 24 September, 2020 at 19:10 Reply

    What is the Part # for a Center sump oil PanKit. Need it for a 2017 5.7L Hemi that is going into a 1967 Plymouth Belverde, I’m keeping the 727 Transmission so I need a Throttle cable that will work the trans also. Need help on part #’s or were I can find some parts that will work with this resto mod. Thanks

    Rear Sump Oil Pan Kit (PN 77072450): Oil pan, pick up tube, gasket,

    • Kevin Shaw
      Kevin Shaw 24 September, 2020 at 20:26 Reply

      That’s a lot of specific knowledge that we’re not going to be able to provide for you. Believe it or not, Holley has dramatically increased it Gen 3 Hemi swap catalog and will be able to provide you with suitable parts to complete your swap. I strongly suggest calling their tech line and speaking with a representative.

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