360 magnum to 408

Whoa, it's not that easy buddy! Slow down. lol Think of what the extra stroke does, more piston travel right? So it is mandatory to have shorter pistons. I would suggest getting a complete stroker kit with crank, rods, pistons, bearings, and rings. Expect to spend a couple grand on the rebuild to a stroker...

....Not including the machining on the block that will be necessary which in the best case could cost another 400-500 bucks minimum.

That's a bore/hone/cam bearings etc etc, and possibly a line hone if you need it.