Supercharging a 440 Stroker
Bob's car rules.
Since this may be new to you, this would be a starting point worth considering (a Dana 60 rear axle):
http://www.strangeengineering.net/catalog/index.html
Don't worry about a block just yet. Not every block you pick up off Craigslist gets sonic-checked and passes to be able to withstand a 700hp blown big block.
You may want to check with 440source.com and see what blocks they have for sale (they are pretty affordable) and if they have a warranty for them or something.
Who knows, you may get lucky with that first Craigslist block though?
Good luck,
Tyson