If using a 904 is an option, in the mildly hopped up scenario I might say its a tie or down to personal preference. I'm not sure if the lighter transmission and reduction in drivetrain losses completely make up for 23 extra cubic inches, but the extra room in the engine compartment will sway plenty to opt for the small block vs the big block. I would still go big block lol, but not for objective reasons.
904 will handle big horsepower. It's also lighter for the human to handle. It is generally safer than a 727 unless a billet ($$$) piece is used in the 727. This is along with the other benefits from my previous post.
In fairness, as built from the factory, the 727 will obviously take much more abuse than a 904.
