I think a big inch small block would be cool. You could easily get 500 - 600 hp out of one on pump gas without too much effort. Or even 700 if you want to push the the race parts on pump gas. But you may need an aftermarket block or a small journal crank and rods at a minimum with a 400 block to get to a 427.
My 632 Iron Dart block with aluminum heads weighed 638 lbs intake to oil pan. The steel shaft rockers are heavy, the dart block is heavy. My 388 with iron heads and aluminum rockers weighed 488 lbs, aluminum heads would probably save ~50 lbs on a small block I would think. The big block is still way faster at the drag strip, but nose heavy.
However a 427 small block vs a 427 big block, I would take the small block, or stroke the 427 big block to a 489 or 496, ha ha
I like big block blocks, a small big block is just extra weight vs a large small block.