2016 6.4 and 8spd swap

rsqrdave

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I have recently purchased a 2016 SRT 392 with 8spd auto 8HP70. The car only had 182 miles and still has the original oil in it. It is going into a 68 Coronet. From all the links and reading I'm going to need a new gas tank/fuel pump system, correct oil pan, oil filter kit, exhaust, motor mounts, radiator and everyone's favorite wiring. I like the Bouchillon tank and fuel pump because there are no trunk modifications needed compared to the Tanks Inc. For the oil filter it sounds like I just need the 45 degree kit to keep it simple. TTi makes both the headers and motor mounts unless there's a better option for both?

As for the wiring here's where I am running into problems. I talked with Chris at Modern Muscle. The industry has not caught up with the electronics needed for the 8spd auto trans. A manual is out, the gf can't push the clutch due to knee issues if she were to have to drive it.

The engine purchased is also missing the power steering pump. Will a modern 6.4L pump adapt without problems to the 68 steering box?

The next big question is the gf also wants it to be nasty, considering running twin turbos from Hellion (if the kit will fit) and exhaust cut outs. Will the stock 2016 exhaust manifolds work or would the TTi header system be a better option.

Starting to think I am in a little too deep. Any help would be greatly appreciated.

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Dreamcatcher

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No help here but from what I have heard and seen there is a lot more involved in that set up. Like speed sensors on the axels and such. But I am sure it can be done and there will most likely be someone here that will chime in with needed information. Good Luck. And keep us all informed.
 

Cranky

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That article was written in 09 and things have become a lot more complicated since then and from what I hear, you even have to contend with the ABS garbage if you are keeping the factory computer and so far, I haven't heard of an aftermarket one. If everything isn't plugged in, it won't start. I may be talking out of my exhaust pipe but. Didn't Ass Monkey Garage drop in one of these engines into a Dart not too long ago and iirc, Hot Rag did an article on it......
 

rsqrdave

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usaroadrunner

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even if you got the 8 speed auto to work, the twins are gonna be hard on the auto tranny unless there more durable than i think. you will probably will have to beef it up. i got the 6.1 with the 6 speed with hydraulic clutch and the pressure on it is really not that bad. i push on the brakes harder than the clutch. lol
 

5.7 hemi

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You need the body control module. There are only a few wires that you'll need to connect from the BCM to the PCM. Basically it (BCM) needs to see that the key fob is nearby (which you don't need) and sends a signal to the PCM (everything is good, go ahead and start) and your in business. I'm not sure exactly which wires you'll need, but it's only a few. That will allow the motor to run as it should, not sure if that will help with the trans.....but hey, a small block 727 will bolt and run well.
 

rsqrdave

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After talking with Randy at Bouchillon it sounds like the 8spd might not be an option at this time, technology has not caught up with it yet. As for the 727, he was saying if the car will be a daily driver the 6.4L with the 727 will wind out quickly on the freeway and for the cost of a Gear Venders a 545RFE might be a better bang for the buck.
 

5.7 hemi

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The 545rfe trans will require tunnel surgery and to cross member modifications. But yes, it is an option and if it was me, I'd toss a coin and head that direction.
 

rsqrdave

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5.7 good advice, whenever I come to a fork in the road I take it. I had planned on some sheetmetal and fabrication work. I am basically rebuilding the whole car again. It will be repainted for the third time by the end of this rebuild. We are planning on doing the full kit from US Car Tool and mini wheel tub also.
 

Sweet5ltr

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I have recently purchased a 2016 SRT 392 with 8spd auto 8HP70. The car only had 182 miles and still has the original oil in it. It is going into a 68 Coronet. From all the links and reading I'm going to need a new gas tank/fuel pump system, correct oil pan, oil filter kit, exhaust, motor mounts, radiator and everyone's favorite wiring. I like the Bouchillon tank and fuel pump because there are no trunk modifications needed compared to the Tanks Inc. For the oil filter it sounds like I just need the 45 degree kit to keep it simple. TTi makes both the headers and motor mounts unless there's a better option for both?

As for the wiring here's where I am running into problems. I talked with Chris at Modern Muscle. The industry has not caught up with the electronics needed for the 8spd auto trans. A manual is out, the gf can't push the clutch due to knee issues if she were to have to drive it.

The engine purchased is also missing the power steering pump. Will a modern 6.4L pump adapt without problems to the 68 steering box?

The next big question is the gf also wants it to be nasty, considering running twin turbos from Hellion (if the kit will fit) and exhaust cut outs. Will the stock 2016 exhaust manifolds work or would the TTi header system be a better option.

Starting to think I am in a little too deep. Any help would be greatly appreciated.

View attachment 365688 View attachment 365689

I had a 15' SRT Challenger (M6), do you really plan on tearing down a factory sealed engine that will last 150k+ miles with relatively low maintenance? You can only run a reliable 6# of boost with the hyper pistons in the 392's before they scatter, here is your best option;
http://www.shophemi.com/p-2562-64l-hemi-6lb-supercharger-kit-by-arrington-performance.aspx

Before you go GV, why not try a higher gearset, 3.23's possibly? A built 727 is bulletproof, I would say it's stronger than the 8HP70 could ever dream of being in stock form (516 lb-ft limit). The 8HP70 is obviously good, but it's nowhere near as capable as the 8HP90 or TR6060.
 
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rsqrdave

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Sweet,
I am in the early stages of this build. I thought I was getting a great deal on it. As I've learned the 8spd may not have been the best. The guys in my car club wanted me to try and make it the paddle shift option. I don't have that kind of money or the skill for that yet.
I agree a 727 is a great transmission. That's what I currently have now behind my 408SB. However I am somewhat limited, with 3:55 it's 3k+ rpms at freeway speeds with my current tires. If we're taking the car out of the area it's easier to trailer then drive it. To me that's the one big flaw of the 727, a lack of an OD gear.

Has the aftermarket caught up with the 8HP90 and the Gen III hemi swaps? The 545RFE is beginning to look like the best option, mainly for the parts available and tech help. The TR6060 is out because the other half has knee issues and if she's going to drive it unfortunately we have to go auto.

I know there's some research that needs to be done with adding turbos/super chargers. It sounds like 6# is about max before piston upgrades. Does a supercharger give constant boost? The kit you linked is 6# would that cause the same problems as turbos? Does elevation play a part in either option?
 
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Sweet5ltr

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Hey Dave,

I'm sure you got a great deal and it's unfortunate you can't run the 8HP70 as it's a killer transmission for a N/A build (just not that great for boost as it hits its limitations quickly). I've yet to see any true aftermarket support for the most part, but the entire vehicle/engine harness is usually obtained in order to run the newer gen Hemi swaps (check out the roadkill hellcat swap with auto+paddles). I'm not an expert obviously on the 6.4 swaps, but most 15-16 model years require a diablo or similar aftermarket Chrysler pcm in order to utilize a tuner ($1,000+ once over and done with/or send stock pcm in for a couple hundred over the tune/tuner cost to get modified). Blowers are engine driven, and you won't make peak HP with a roots/twin-screw but you'll make incredible torque down low. Procharger intercooled centrifugal kits supposedly have the best power output with stock internals (200hp+ gain), but really, anything over 6-7psi is a gamble without the drop-in piston upgrade from Arrington.
 

rsqrdave

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I've read a few articles about General Mayhem. There's was a cut and patch build. Their setup they "duct taped" the taillights from the donor Charger along with some other items like the cluster, center console/shifter, and steering column. They needed the taillights to make the BCM work correctly.

I unfortunately passed on a Hellcat engine and trans. Figured it would be too much work to make it happen. Sounds like that would have been a better deal.
 

coronet68mx

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There is this guy in YouTube Shelbydogg he have a few videos about how to start a 5 .7 without the Chrysler pcm he use a msd 6 and ez fuel system you should check it is very interested idea
 

Cranky

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Man, this stuff is making my head spin lol. Watched a hot rod vid on youtube the other day where they made around 600 hp using a stock bottom end 5.7 with a centrifugal blower on it. The belt kept slipping at the top of the dyno run with the numbers falling off. The hot rod crew even used headers with no dents!
 

Sweet5ltr

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Man, this stuff is making my head spin lol. Watched a hot rod vid on youtube the other day where they made around 600 hp using a stock bottom end 5.7 with a centrifugal blower on it. The belt kept slipping at the top of the dyno run with the numbers falling off. The hot rod crew even used headers with no dents!

No dents, no way :bs_flag:
 

Cranky

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No dents, no way :bs_flag:
You saw that vid that someone posted on here where they did a dyno test with good headers and dented ones to see what the difference it would make, right? It was funny and surprising. They didn't swap headers but put dents in them...then more and more and more lol
 

Dreamcatcher

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There is this guy in YouTube Shelbydogg he have a few videos about how to start a 5 .7 without the Chrysler pcm he use a msd 6 and ez fuel system you should check it is very interested idea
Great information...if you can follow lol. He understands all that computer stuff way better than I do. Seems more cost effective to just go with a reprogramed stock ECM with premade harness. IMHO
 
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