That combo would make more like 544hp. For my 512 I bought my own parts and went with a
4.25 stroke, longer 6.7 rod, and a 1.12ch piston. Which is a shelf piston for the 4.15 kits. Longer rod and lighter piston. I think the kits should come this way. Rather than the 4.25, 6.535, 1.32ch.
650hp with a similar combo will take a fully ported head and likely more camshaft in the real world