Gen 3 HEMI Torque upgrades?

So, a little context. Right now I have a built 360 with a 268 cam that makes 438 lb/ft at 2500 rpms and it peaks at 467 lb/ft at 4500 rpm (to the crank). I was thinking of swapping in either a 6.1L or a 6.4L, my questions is what upgrades can I do to the HEMI to make that amount of low end torque at the crank (even better if it was to the wheels) without having to go with a supercharger.

I've seen dyno videos, posts, and the videos on shopHEMI.com but most of those are supercharged. Is it really that difficult to get that power down low? And yes, I love having that much power down low.