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1979 Dodge Demon - The EBay 5.7 Hemi Engine

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We promised to install a Hemi engine into our Dodge Demon, and that time is here. A quick search using the keywords "5.7 Hemi engine" on our eBay Mobile app netted us about 50 different used Hemi engines of various years with a wide range of mileage. As this is written, the average was $2,000 for a 5.7 Hemi engine from a truck and $4,500 for one from a Charger or 300C. We chose a 5.7 hemi truck engine with 65K on the clock for $1,900 from eBay seller Knox Auto Parts. Knox is a wholesale salvage yard in Knoxville, Tennessee. The total price of the Hemi engine with shipping was $2,203.99. For that, we received the complete engine, a wiring harness, and a starter.

After the engine arrived, we needed to learn how to get it running. To get some advice, we called the guys from Street and Performance, MegaSquirt, local tuner DC Motorsports, and even the guys at Comp Cams to get the rundown on what is available to control and tune a Hemi-swapped vehicle.

The options in this story will work on a stock 5.7L truck engine or one pulled from a passenger vehicle. If you go cheap and buy the truck version, you are stuck with a dedicated factory manifold. Passenger-car fuel-injection manifolds crash into the timing-chain cover, making that swap impossible without also swapping the matching front dress. That adds at least another $300 for the cover, plus about $75 more for a plastic intake. The aluminum 6.1L intakes and fuel rails can cost as much as $1,000, and unless you plan to use an alternator-only front-engine accessory drive (FEAD), as we are, you will have to change the FEAD as well. Picking the wrong combo of parts can get expensive, fast. Keep that in mind when you make your choices.

Hemi Engine Factory Harness And Tune

We are adding this option because, in theory, you can add 12-volt power to the stock wiring harness and get the Hemi engine to fire and run on the factory tune. Yes, this is the cheapest way to go, but if there is a wiring problem somewhere in the nest, there is no tech line to help you. Mark Campbell from Street and Performance (S&P) in Mena, Arkansas, explained that the key to making this work is knowing the year of the engine and computer and getting the VIN of the vehicle. Campbell says the '03 to '05 computer is the best. It is less complex because it does not run the computer signals back and forth through a single wire like on the '06 to '08 harness, and S&P hasn't been able to get the '09-and-later system to function with the variable cam timing outside of the vehicle. He also mentioned that some vehicles were equipped with antitheft from the factory. It will kill the ignition if it is not removed from the computer. (Call Mopar and check the VIN for this feature.)

Campbell agrees that the simplest way to get a used Hemi engine running is to use an '05 factory harness and computer, a truck gas pedal, and a pedal-positioning switch (PPS), assuming you use a manual or early-style automatic transmission and an adapter plate (which can be purchased from S&P). If you do not need a detent cable (if you have a manual trans or a manual valvebody in an automatic, for example), you can use an '05 truck pedal with a built-in PPS. If you want to use your stock muscle car pedal or need a detent for a kick-down, you can use a stand-alone PPS and a set of Lokar cables to get it all to work.

If you want to add more power later, you can tune the computer with a handheld tuner and a dyno day. If you want tech support, we'd recommend purchasing a dedicated harness. S&P's team can only answer questions if they know what you are working with.

How Much?
Description Source PN Price
5.7 Hemi engine harness (manual trans) Street and Performance N/A $927.95
Dodge truck pedal Street and Performance N/A 139.95
Pedal-position switch Street and Performance N/A 259.95
Total $1,327.85

Factory Harness And SCT Or Diablosport Tune

Once you've sorted the factory computer and harness, you can access it with an aftermarket, handheld programmer. We spoke to Chris Jensen at DC Performance in west Los Angeles for the options. He says that for the '04 to '06 Hemi controllers, the SCT tuner can be used to upload basic cold-air tuning maps. All you need to do is call the company and explain what you want, and SCT will email you the program to upload onto the system. If you want to tune the car yourself, you'll need the Pro Racer software and some kind of data logger for dyno runs or some time on a chassis dyno.

For the '07-and-newer Hemi, you'll need the DiabloSport tuner that works in the same way as the SCT, by downloading programs that are included with the tuner or ordering a custom tune based on your needs.

"The '07-and-newer Hemi controllers can be more difficult to work with, and disabling the antitheft security can be much more of an issue than with the '05 to '06 Hemi controllers. Even if you have a '07-and-newer engine, it is advisable to use an earlier NGC3 controller from '05 to '06. You can also minimize problems by ordering a factory-fresh controller, since the controller will not have been ‘married' to a vehicle," Jensen says.

We're not kidding ourselves—we'd likely need to order the tuner and the Pro software and pay a dyno guy to dial in the car. We also learned that these tuners require the drive-by-wire pedal mentioned above, which we did not get with our used engine. According to Jensen, the drive-by-wire system works with the computer to calculate the power output needed rather than just sending a WOT signal, so a factory pedal and the pedal position switch is needed.

How Much?
Description PN Price
SCT tuner 9550 $379.00
Pro Race software N/A 349.00
S&P Dodge truck pedal N/A 139.95
S&P pedal-position switch N/A 259.95
Dyno day N/A 1,000
Total $2,127.90
Optional DiabloSport tuner U7137 309.00

MegaSquirt

We've heard the MegaSquirt is the most interactive way to fire up a fuel-injected engine. It's low buck for sure, coming in at $675.94 for the solder-it-yourself MS330 MegaSquirt III and a basic wiring harness. According to Matt Cramer at DIY Auto Tune, for that price you get goodies like sequential fuel injection with individual injector timing and pulse-width control, a data logger, progressive nitrous control, boost capabilities, and extra outputs for electric fans and fuel pumps. The MS330 controls the ignition timing but is designed to work through a control module that amplifies the spark. The company recommends a pair of four-cylinder Bosch control boxes that cost about $180 each.

The throttle pedal issue is partly solved. You can use any cable-operated throttle-body that has a throttle position sensor, including less expensive GM LS parts, if you can build an adapter and plug it in the system. At press time, BBK told us of a Hemi cable-operated throttle-body it was developing, but it did not yet have a price or part number.

To take advantage of the data logger, Cramer recommended a wide-band O2, like the Innovate LM1, which adds another $249-plus a day at the dyno to get it dialed in.

How Much?
Description Source PN Price
MS330 DIY Auto Tune MS330-K $675.04
Bosch control box (2) DIY Auto Tune 0227100211 180.00 (each)
Cable-operated throttle-body BBK N/A Call
Dyno day Westech Performance N/A 1,000.00
Total without throttle-body $2,035.04
Optional wide-band O2 meter Innovate Motorsports LM-1 249.00

FAST Crate/Transplant Engine Management Kit

The guys from FAST told us the company's installation kit is so complete that you need only an engine, a fuel system, and a battery to get things running. The kit includes the XFI system, the XIM ignition module, a 92mm cable-driven throttle-body that uses a standard Lokar LS cable, and the correct wiring harnesses. There is also a tech line if you get lost.

The system itself goes way beyond the base maps that are provided. It has several high-tech features, such as 5 bar MAP capability (for boost applications), either bank-to-bank or sequential fuel-injector control, boost control, A/C, the XIM ignition controller with adjustable timing curves, and a rev limiter.

The kit works with both the 5.7L and 6.1L, and even the 6.4L. The total cost for the system—plus a recommended dyno day to tune it—is more than 4 grand, but you can expand the system indefinitely, including adding traction control, a 16-injector option for huge power output while maintaining finite control, and internal data logging with 24 inputs. You pay a little more for stupid-easy.

How Much?
Description Source PN Price
Crate/transplant engine management kit FAST/Comp Cams 0227100211 $3,234.15
Dyno day Westech Performance N/A 1,000.00
Total $4,234.15

Mopar Performance Controller

Mopar also has a system to get a 5.7L/6.1L running. It is the most expensive of the stand-alone kits, but the AEM controller gives you complete control of everything and comes with start-up calibrations for 5.7L truck and car engines. Using a laptop serial port or USB interface, the software allows access to all the fuel and spark tables, wide-band 02, and everything else that comes on a factory vehicle. The average dyno guy will be able to tune this on a laptop. It can also run non-Chrysler transmissions, like a 4L60E GM trans, that will fit your B-Body via a bellhousing adapter.

The company sells the controller and harness together, and while it works with any '03-and-up truck or car, it is designed for '06-and-up coil setups, so you will need to know the year of the engine you are working with. If you want to run an older engine (pre-'06), you need to have the factory connectors for the coils and splice them into the new harness. The controller does not come with a throttle-body or cable, so you will need to buy the yet-to-be-released setup from BBK.

How Much?
Description Source PN Price
'03-later swap kit Mopar Performance 05153921 $3,166.00
Cable-operated throttle-body BBK N/A Call
Dyno day Westech Performance N/A 1,000.00
Total $4,166.00

Carburetor and Intake

We've been told it's not the cost of EFI that turns people away but rather the complexity of installing it. For those guys who like it simple, there is a carb and intake option. The single-plane manifold is offered from Mopar, and it will bolt to either the truck or passenger-car 5.7L Hemi. According to our sources, it will not work on the 6.1L. To run the coils, MSD offers its 6-Hemi controller for both early and late coil packs (late packs have no plug wires), but you have to buy a specific wiring harness to make it work. The MSD has the standard goods, like a two-step rev limit and custom timing curves. For an ultra-low-tech option, Arrington Engines sells the ChipKillr (see www.shophemi.com). It is a custom timing cover with a mount for a distributor, so you can run the Hemi with no electronics at all. It retails for $2,099. The manifold is expensive at around $800 MSRP, but you don't have to buy a gnarly fuel pump to run it, and if you add heads, cam, and a blower, you don't have to buy expensive injectors and retune on a dyno. You can find a good carburetor-tuning book just about anywhere if you've never done it before and need some guidance.

How Much?
Description Source PN</td> Price
Hard Core Ultra HP 750 carburetor Holley/Summit Racing 0-80803HB $719.00
6-Hemi control box MSD 6013 513.00
Control harness MSD 88864 185.00
Single-plane intake manifold Mopar P4510581AB 828.30*
Total $2,245.30
*www.oemmoparonline.com

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