I like your plan. Lighter crank (slightly) lighter rods (than 440s) lighter forged pistons ( compared to cast stockers, WAY lighter) lighter pins. Should rev like mad, better than a 383, and probably a 340.
You will need really good heads and the right camshaft to allow it to make power at those high revs, however.
Interesting build. Problem with standard stroke 400s has always been pistons, your build solves that without building a big stroker.
Have you checked out that 8000 rpm 327 build on engine masters? 7500 rpm 426 should be fun.