6.4 hemi charging system?

There is no reason, really to "convert" the old unit. THE MAIN REASON any charging system other than "one wire" give you voltage trouble is

1...The alternator AND regulator MUST BE grounded to battery negative. In other words NO voltage drop

2...In the same vein, the battery voltage supplying the VR MUST not have voltage drop. This is the path through the ignition switch. You probably need to add a relay to key underhood loads, including the VR

BUT IF YOU DO, AGAIN, research a large enough charge wire AND FUSE / BREAKER protect it.