Maybe you are just putting the 6400 cab on the 2500 chassis. If so, you are just building a 3/4T truck.
Maybe you can spell it out more in depth.
What do you want to do to the 2500 and what do you want to do to the 6400. One at a time.

Myself, I'm not sure what you are doing and what drivelines you are asking about. Not sure what motor. Not sure if you really mean a frame swap. It sounds a little like a chassis swap. To some folks, it's the same. To some it's not.

Coilover has given you good advice.


Right is right, even if everyone is against it, and wrong is wrong, even if everyone is for it. - William Penn