If it were me and I already had all of those parts, I would definitely do the 440 with a modern cam grind and let it rip. You already have excellent numbers from the 5.9 Magnum. You already have most of the parts for the comparison. And, you have a youtube channel where we can watch the build and results as you go. Everybody wins. And I think the 440 will win in that scenario too just because the heads will move more air. But, only one way to find out.
Whichever way you go, I approve and I will watch the videos. Good luck and keep up the good work.