gen 3 hemi swap in a j body?

miradadave

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Has anyone attempted a gen 3 hemi swap in a j body yet? It seems doable to me.

In thinking, early 5.7 block with stroker crank (392 cu in), ported 6.4 heads, drag pack intake, 950 HP carb, custom headers, SB 727 and Dana 60 outback.
 

kkritsilas

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No expert, just passing on some things I have learned.

The biggest problem is the electronics and transmission. The Hemi is fuel injected, and the fuel system on the J body can be modified to work with a fuel injected car. However, the fuel injection computer also operates the ignition system (it is a direct fire, coil on plug, or in later systems 2 coils on 2 plugs, per cylinder). Aftermarket has figured out how to get the ignition to work, and there are carburetor intake manifolds as well. The transmissions, at least in automatic form, are a problem, in that they are also operated by the fuel injection computer. As far as I know, there are no plug and play stand alone controllers for things like a 545RFE or newer. I have heard rumours that this has recently changed, but I haven't seen any real products being advertised. The older transmissions (3 speeds like the A904/A727, or 4 speeds (A500/A518 or 42RH/46RH)) have LA bolt patterns on the bell housings, and don't mate up. Alternatives like the TCI 6X do, but for a price ($6-7K).

This is, still, a fairly high cost swap. It may be cheaper to build up a Magnum, or put Magnum heads on an LA block to the power level of a Hemi, than to try to make a Hemi work in our cars. With a well though out selection of parts, and a good engine builder, the costs will probably be significantly lower when the overall car costs are considered. Getting 5.7L Hemi level power (375 HP/Torque for the street) wouldn't be hard on a 360, or possibly even a 318, with good street manners, and good performance.

I would be happy to be corrected by people who know more than I do, or have later news than I do.

Kostas
 
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Joe12459

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I'm working on one right now. I bought a 2008 Charger, and I'm putting the engine, trans and entire electrical system and interior in an 83 Mirada. So far, I've learned that the drivetrain physically fits in the Mirada. I used an AlterKtion K frame and a rear sump oil pan, and mounted the engine a little more forward than a stock small block would be. The exhaust on the right side will probably be challenging, but otherwise everything fits. I think the Charger fuel tank will have to go in the trunk, which will free up some room for exhaust. Out back, I used a 67 B Body 8 3/4 rear and shock plates/shocks, on stock Mirada 5 leaf springs from Springs N Things. I'll update as I make more progress.
 

Monkeyed

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I have to agree that it would still probably be harder nd more expensive than a magnum, or LA build up, with out much advantage. If you're going to keep the electronics, that might be a different story.. if they're just going to put a carb on, why go to the extra expense, and effort. just seems like something that will look good on paper. admittedly, I'm no expert on the subject.
 

Monkeyed

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I'm working on one right now. I bought a 2008 Charger, and I'm putting the engine, trans and entire electrical system and interior in an 83 Mirada. So far, I've learned that the drivetrain physically fits in the Mirada. I used an AlterKtion K frame and a rear sump oil pan, and mounted the engine a little more forward than a stock small block would be. The exhaust on the right side will probably be challenging, but otherwise everything fits. I think the Charger fuel tank will have to go in the trunk, which will free up some room for exhaust. Out back, I used a 67 B Body 8 3/4 rear and shock plates/shocks, on stock Mirada 5 leaf springs from Springs N Things. I'll update as I make more progress.

I'm curious to know how the computer takes it's input for the trans, since the old one was mechanical.
 

Joe12459

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I'm using the 08 Charger trans and all running gear, so the electronics should all work, with the exception of traction control/ABS. Hopefully.
 

Monkeyed

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I'm using the 08 Charger trans and all running gear, so the electronics should all work, with the exception of traction control/ABS. Hopefully.

are you installing the floor shifter out of the charger then?
 

Joe12459

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Yup, I'm installing the entire interior, dash, gauges etc. While it's a lot of work, I think it's the best way to get all of the electronics to work. I have the dash mocked up, and it actually looks good. I have to fabricate mounts for the HVAC box, but otherwise everything seems to fit.
 

Monkeyed

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Yup, I'm installing the entire interior, dash, gauges etc. While it's a lot of work, I think it's the best way to get all of the electronics to work. I have the dash mocked up, and it actually looks good. I have to fabricate mounts for the HVAC box, but otherwise everything seems to fit.

awesoome! welcome aboard btw
 

Dr Lebaron

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I have to agree that it would still probably be harder nd more expensive than a magnum, or LA build up, with out much advantage. If you're going to keep the electronics, that might be a different story.. if they're just going to put a carb on, why go to the extra expense, and effort. just seems like something that will look good on paper. admittedly, I'm no expert on the subject.

I'd like to say there are lots of gen 3 advantages.
-Uses todays junk gas.
-Parts are plentiful.
-Modern mechanics can work on it with ease.
 

Monkeyed

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I'd like to say there are lots of gen 3 advantages.
-Uses todays junk gas.
-Parts are plentiful.
-Modern mechanics can work on it with ease.

if they convert it to a carb it won't run the gas any better. I'll give you there are plenty of parts around, but you'll probably NEED a mechanic to work on it..
not sure all that outweighs spending and extra $10k+

to each their own, if I had the cash to pick up a wrecked hemi car, I'd consider it. I don't know, seems like a lot of headache that I personally don't have the time, cash, energy, or resources for.

but hey, more power to him. :icon_kidra:
 

kkritsilas

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Using today's junk gas with a Magnum/LA is no issue. Biggest problem with ethanol in modern gas is the fuel lines (which, if you are rebuiiding a F, M, or J body anyway, should probably be replaced, so replace them with fuel injection hose that can stand up to ethanol), and the floats/seats in the carbs. You can buy brass floats, and clean the seats of any deposits, or go with a Street Demon carb, which is sort of the modern reincarnation of the Thermoquad.

There are easily more parts, and far cheaper for the LA/Magnums than for the Hemi. A air filter for an LA is about $4-5, Hemi is close to $20. Same with oil filters, athough the price difference is lower. LA/Magnums can use standard copper spark plugs, not sure that the Hemi uses copper, but I would bet that they are platinum or double platinum. Most other regular maintenance items are the same cost, but being cast iron, the Magnum/LA blocks are not as picky about coolant as the aluminum headed Hemi. Again, speaking from ignorance here, but Magnums/LAs get along fine with conventional engine oil, Hemis may require synthetic (but not sure about that).

Modern machinics would probably freak out if you brought an F, M, or J to them. First thing they would start looking for is an ODB II connector. If you have brought the whole drivetrain and wiring harness over, they may be able to work on it. More likely though, and especially if you have not used all (and I do mean ALL) of the factory original parts, they will be lost, or just not even look at it. Also, if the intent of this hobby is to be held to, you shouldn't be bringing your car over to "modern mechanics". If you want a factory spec. modern car, buy a factory spec. modern car. Long term, it will cost less than taking a drivetrain/wiring harness out of a newer car, working out how to get it to work in our F, M, or J Bodies, and you will be able to bring it to a "modern mechanic".
 
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Monkeyed

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getting kind of 'thread hijacked' here. I'm not against the idea, by any means, I love seeing things that "can't be done". If I had the money, and time, I'd be all over something like that myself.
 

brotherGood

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IIRC, XV Motorsports has a carb kit for the HEMI. It's pricey, but stupid easy from what I've heard. If you've got the time and money, go for it.
 
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