Can this be duplicated with a 5.9 build??

OOps yur right, yeah 430torque is doable with a 5.9, but I can't see it at 2400 normally aspirated.
Sorry I screwed up.
Exactly, the OP was asking about a motor that would equal the 450 ft lb torque at 2400 rpm. To get that torque at that low of a rpm with a less cubic inches, he will need boost, and I am thinking a positive displacement supercharger or an undersized turbo that spools early would be the way to get there.