Holley/Demon Carb stumble (posts 472 - 491) See in particular the sketches of Cudafever's system in post 485, and his tests (488-491) that show lower pressure allows more volume to the carb.
If you ever have to mess with pressure and delivery, the posts that link goes to may be very helpful. Depending on the regulators and arrangement (dead head, bypass after or before), higher pressure at the regulator can reduce delivery volume to the bowl!