Sounds like you are real close, takes a little time but feels much better when you can make it better yourself. I don't have a definitive answer on a BBC intake, although have always found the Edelbrock intakes to be the best on my SBC's. You can try an open spacer to give the intake a common plenum. A dual plane makes the engine think you have a smaller carb, thus the increased throttle response at lower RPM's. You have to decide where you will spend the most time, anything over around 4000 will give way to a single plane as long as the carb is not too large and you are OK there. The positive of a single plane is that fuel distribution is much better, dual planes tend to have rich and lean sides. With no other knowledge if you decide to change my choice would probably be the Victor Jr. Smaller runners and plenum to keep the velocity up.