The bottom end is great, I agree. My inliners chug all day at 1000rpm whereas my v8's need a few revs.
Its just the application. With a few boltons and not getting too into the internals of the engine, the 400 simply makes more power higher in the rev range. Not to say my 82 or 75 dont see the woods, the 292 in my 75 is a great runner and makes plenty of power. I actually prefer the inline 6 for most situations outside of all out bogging.
I got the 427 talldeck on the stand and thats nearing completion and awaiting a home. Next in line im doing something special with the 292 that was originally in the 84..Im thinking a Gm throttle body retrofit along with some internal work.