That will get very expensive very fast. The issue with swapping and upgrading engines is that the current ECU is not tuned or set up for it, and the transmission might not be able to handle the increase of HP and Torque in a way that will allow smooth shifting. It might just need a torque converter upgrade, or could need a different transmission. Hopefully someone else will chime in on this, because I'm just thinking out loud with the theory.

 

this was on a Gen 4, https://www.ramforumz.com/threads/5-7-to-6-4-swap-with-pictures.240258/

Since you have a Gen 3 I know you'll need at least new mounts on motor, plus some wiring changes. You can try contacting Bouchillon Performance as they sell lot of kits for doing Hemi swaps, my buddy is using their stuff to put a 5.7 into a Dakota.

Also, are you talking a SRT 6.4 or a truck 6.4? If so, there will be lot more to change over if it's a SRT motor ( I know intakes are different but may still be able to use it if SRT, prob have to use a CAI). If it's a truck engine look up the HP specs on your motor. Stock tune on the 6.4 may give you 65extra HP or only 17. (If 17hp diff, a much cheaper way to get more than that would be a hotter cam and tune)

If you do pull the trigger and do it, keep track of what you had to buy and what changes were made and post them here to help out other guy.

 

Literally depends on what year you have; not all 3rd gens are the same. Clarify that, then we can go from there.

 

Thank you all for the insight. Realized I did leave out some details. My truck is an 08 4X4 with 220,000 miles. It has sentimental value so I am willing to “waste” some dollars to restore it. I am planning on doing a complete drive train upgrade. I have found several “Turn Key Pallet” packages from different shops. Does anyone recommend a shop or vendor? I am in West Texas.

 

Since you have a later 3rd gen (CAN bus) this a relatively straightforward swap. Your stock RFE trans will not handle any 6.4 for long.
Luckily you don't need a standalone controller (though it would be better but vastly more expensive). The 2009 2500 is a 3rd gen platform but has a 4th engine in it. The PCM from a 2009 2500 will integrate into your 2008 architecture but will run a VVT engine (unlike your stock one). This also means all the accessory drive, etc for a 4th gen engine in a 3rd gen platform exist as factory parts:

Just need the PCM and engine harness.
4wd 8HP70's are easily had and will tolerate a 6.4 (just need the trans tuned to handle it). Having 4wd makes life a little easier since you don't need custom driveshafts. Just need a custom trans mount.
You WILL have to figure out where you're going to mount the electronic shifter (this is non-negotiable) as you will be losing your cable column shifter.
The required retrofit harness for a ZF trans is expensive and is also non-negotiable.

 

If you want a performance motor, try shophemi.com (formerly Arrington, they still sell their specialty parts.). You can order a mild motor all way to "holy sh*t did I need new undies" kind of motor (and they make the motors for Direct Conection, Mopars performance division. Or Bouchillon Performance, they been around since I lived in Charleston back in the 80's.. they offer warranty on their crate motors.

If stock, try Jasper or even Ram itself (you'll need a VIN from a 2500 with one to order it), but I don't know if their warranty will conver a transplant rather than direct swap.

 

Thank you for the info.