Why does Edelbrock cut some plenum dividers and not others?
True, at idle, the draw on the carb is light and the primaries work as intended, one side feeding one side of the intake.
When your at WOT, the draw on the carb and through the intake really starts moving. The cut in the divider helps balance. The older LD340 is like that. On older manifolds, the cut is big in order to provide a clearance for the carbs that were put out by Holley and Carter that were 3 bbl.'s. Normal primaries and 1 big huge door for the secondaries. The intake needs to be clearanced for these carbs.
I don't know why the dividers are the way the are on each intake, but I can only assume, that was found to be the best thing to do for the intake for that brand in the RPM band intended and the general performance intended for that intake.
(This 3 bbl. carb is the foreruning thought behind the spreadbores they used later. The T-Q is a race carb from birth, OE stocker second, adapted to a smog carb later.)
If your looking for some extra power out of the intake, you should look to a spacer. The engine combo should point the way to what would be best to use. What carb do you have on top now?