For what it's worth, the Engine Masters' Challenge guys are barely getting the EFI set-ups to finally out-power carbs and that's with using state-of-the-art electronics, carefully placed injectors, and individual cylinder air/fuel ratio and timing mapping. I think an OEM throttle body that's been necked way down to fit, set on an extremely inefficient log manifold that only uses 14 psi injectors without any of the benefits stated above is gonna be extremely hard-pressed to compete with a well-tuned carb as far as power is concerned.
There are other, obvious advantages to EFI that a carb can't compete with but the question is about power.
Just my opinion, however.
Edit: A good friend of mine, Mark Dalquist, (he's the builder of the engine below and is the man standing in the doorway of the dyno cell with the dude holding a camera above his head) will apparently grace the first page of the EMC spread with his Pontiac entry. He won the award for the best "classic" entry: meaning non LS, non Modular, etc, but I can't remember what that award was called. Either way, he'll also be awarded a full center spread on his Pontiac build in an upcoming month of Popular Hotrodding Magazine. Ok, there's my semi-shameless plug for a friend and the magazine that allows badazzes to be badazzes.
Here's a pretty sweet test of an EFI engine. Mark told me after-the-fact that his dyno carb (950 IIRC) was up nearly 15 HP on the EFI numbers seen here. They nailed it this year and beat the carb but it took a lot of work.
Point is, if it's power that you're looking for, a well-prepped Weber 38 is going to be extremely hard to beat. If you're after the cold-starts, the off-camber stuff and not having to worry about jet swaps for altitude/seasonal changes, etc., EFI may be the ticket.