360 Stroker Combo Build Questions

Mopar 440ci smallblock crate motor. 540hp, 550lbs/ft.
Here's the link:
http://www.bouchillonperformance.com/P5153523.asp

Pretty sure that would have to be an aftermarket block. Someone correct me if I'm wrong. I have a .040 over factory 340 block with a 4.082 bore that has some pretty thin walls after sonic check. I'm thinking the walls would be see through at a 4.180 bore on my block.