Hi torque at low rpms is what the auto industry tries to make. And the recipe is long tubes manifold with FI,and free flowing exhaust tuned if possible to low rpms. Good flowing heads make up for the modest cam in the upper rpms.
It is much easier for a hobbyist to achieve the high torque in somewhat higher rpms, as ram tuning then does not demand insanely long tubes, and commercial headers are on the spot. This is what makes me wonder how the 600 lbs can be achieved with the described combination at those low rpms. (And do not forget: 500++ lbs down below will also kick butt!!) Is the 2-barrel intake path in the 6-p setup so efficient? This is not criticism, but I am not sure if it is correct. Please allow me to make such a comment, as I struggle for the best results myself (knowing how hard it is to hit correctly), and I am always interested in new-thinking. Maybe the desktop dyno has a black spot down low rpms (like calculating high VE due to "ram tuning")?
And, I would really like to get some tips, as I live in a dark side of the world with pumped up gas taxes, and heavily taxed modern cars (but not the old ones!) so making engines this way is somewhat of a target. If, for nothing else, to feel the torque and hear the sweet V8 rumbling.... And, I have been working with Mopars since 1973, but I am not an "expert" (LOL)