Hi chpewah . . .
I think that I follow what you want to do. Almquist used to sell these adapters to put on top of a stock manifold. Charlie Price at vintage speed sells a repro now:
But is there really enough space between the throats on an dual offy to fit two of these?
I also wonder how well it would run with so much carburation. But you could always block off two of the four and get the show without the hassle of synchronizing four carbs.
good luck
stock49