6.4 swap

[1973]

Hi, I was always thinking a 440 or 400 swap into my 73 cuda, but now wondering if a newer hemi would be a better choice, would like to see around 600-700hp, automatic transmission, what is the the best bang for my buck? Do I go used with all the parts? (Wiring, pedal) I saw a hellcat engine/ trans for 12,000, good buy? 8,000 miles,, . is one of the newer trannies a good bet? Or will a old 727 work out? Are there mount kits available? Or do I go with a new crate unit?

 

[DrEamer]

Unfortunately, no one who has done a Gen 3 Hemi Conversion here is answering, so I'll give you what I do know about it from the research that I have done when I was considering it myself. All the parts to put the Hemi in are available (Engine mounts, oil pans, control units for the EFI and ignition system, and pedal wiring ) A 727 will work, you just need to get the conversion flex plate. If you want the newer transmission, the tunnel will need to be modified/ fabricated to work. Also, if you plan to run that much horsepower, then you will need to stiffen the chassis. I really can't answer whether the used unit you are looking at, or a crate engine is a better value, since I was looking at a 5.7 Hemi that I planned to modify. As to the best bang for the buck, that is a hard call. I started down the path of a 470 stroker, and am just doing a modified 5.9 Magnum with a Holly Sniper EFI and ignition system. My reasoning is that it is fairly strait forward installation, plus I scored the engine and A518 overdrive transmission core at a great price. I hope this helps.

 

[1973]

Ok, thank you, so how much horse power are you getting out of your combo? What transmission are you using? Also you said you were starting with a 5.7 then went with a 5.9? So none of the newer hemis are any better than others? I just picked the 6.4 as it was the biggest, thinking no replacement for displacement. Also is it allowed to tell me the best places to source the parts? ( Mounts, pans, controllers, etc)

 

[DrEamer]

As far as horsepower from my combination, it should be in the 425 to 450 range, with about the same for torque. I could get a bit more if I stroke it to a 408. The transmission is a A-518, also known as a 46RH. My first thought was a 470, but then bought the 5.9 Magnum. I looked into the Hemi, more out of curiosity then anything else. As far as sources, Milodon makes the oil pans, Schumacher makes the motor mount, and controllers are made by Mopar Performance, MSD, and Fast fuel injection among other. I am sure the list of suppliers is growing, as it is getting to be a fairly common conversion. There are some shops that are selling kits, but it has been a while since I checked into it. In this case Google is your friend, along with some phone calls.

 

[Hubes71]

I'll through in my two cents. I installed a stock 5.7 into my 71 Challenger with an 833 4 speed. I started the project back when 6.1 was the big one and hard to find. Even at 345 hp, the car is really fun to drive, you will not regret going Hemi. I would suggest that you go as big as you can afford. Parts are easy to find now like DrEamer said. I would recommend dropping the Drive By Wire, going with a Borgeson steering box, and using an aftermarket computer.

 

[Sublimeone]

I am in process of installing a 6.1 modern 6 speed Tremec behind. Contact Hotwire in Ark and ask for Chris he really saved me a bunch of wiring hassle. Send me a PM and I can elaborate if you want.
SLO

 

[rolling_thunder]

Have a 6.1L in my 68 Charger - did the swap way back when only a couple people had done it (2008) -- Originally did a 5-speed and currently swapping in a T-56

mounts, headers, etc are all available. Car is very fun and very reliable.

 

[Cudazilla]

If you are shooting for 600-700 HP power range, you need preferably forged internals in a gen iii setup and boost it with a supercharger. It's pretty easy to get 500 to the wheels with just a cam and a few Bolt ones like headers and a throttle body on a 392. A manual trans is a easier swap as there no computer controls involved. A 727 with a gear venders is also great without any cutting to the floor. But like others are saying, a 5.7 runs really nice too!

 

[hpjunke]

I have done a gen 3 swap and like stated before contact Hotwire auto. You will need to have them make you a harness for the hellcat but the oil pan headers and mount adapters to make it sit in the bay . I did a thread on how i did my swap at the time i had a stock k member in it , i have a tubular qa1 in it now but i covered a lot of what you will run into doing this kinda swap ..

 

[Cudazilla]

To add to that, a 5 speed nag1 transmission, hotwire auto sells a harness and Chris can set you up on what pcm you might need. Also modern muscle xtreme sells a harness kit for the same swap with pcm, pedal harness and a tune for it. If using a non computer controlled trans like a 727 with a gear venders, a A41 which is a (hate to say it) Chevy trans with a chrysler bell housing, or a manual trans you can go with a Mopar crate hemi plug and play kit, but requires a 2014 and newer 5.7 or 6.4. I think you can possibly go to a 2009 vvt engine with this set up as long as you change the reluctor wheel on the crank to a 58 tooth and update the crank sensor as well but don't hold me to that. If you have some wiring skills you can even make your own engine harness by going to DYI Hemi.com and check out the pintouts of the pcm and wire your own relays. And they cover 2003 to present hemis. Hope that helps out!