Install a Rochester 4-bbl intake from any small block Chevy and bolt your carb on. I doubt that you'll see any significant improvement, though, because the manifold intake runners will probably be bigger than the head ports and will likely cause turbulence at the manifold/port interface.

Don't even think of trying to use an adapter between the 4-bbl carb and the 2-bbl manifold. All the geeks down at the drive-in will laugh at you.