The big block always wins...if you can get it to hook. Bigger bores, wider bore spacing, taller decks all make more power.

Let's say you build two engines, both 400ish CID. The BEST you can hope for on the small block is a 4.250 bore. On a BB platform you can easily go 4.500 with a much shorter stroke. Now you can shorten the decks (saves weight amongst other issues) and you'll have bigger valves and room for bigger ports. Plus, you can RPM the piss out of it and RPM makes horsepower.

All one needs to do is look at Pro Stock (or what's left of it) and see they run the biggest bores with the shortest stroke and RPM (until NHRA killed that).

It's simple physics really. The BB wins every time. Unless you want to talk Modified or Comp eliminator stuff. Even then, small displacement BB architecture has advantages unless you can get the car light enough to benefit from the SB architecture.