Single pane vs Dual pane

h340, the best you can do with a dual plane is what moper said. Another trick is milling the center divider. But this mod is more for a race set up that requires a dual plane intake. Your making mods to help it out. The divider mill is a permaent mod that kills some low torque.
With the exception of the RPM and probably the stealth, all dual planes will need these mods to help it outbeyond what it is cast for.
It is simply better to get the intake swapped out.
383mans example is an excellent one.

Mike, I think your right only followed by the "B" 400 once it gets a piston change for some decent squeeze. Problem around my way is actually finding one these days around my way.