Frackster - There would be drilling to match some of the intake bolt holes as well as aluminum welding and porting to match the port shapes.

It might be easier to port out any mismatch on the head side if there is enough material there. But it would be kind of a tacky way of doing it. It's been a while since I had some. An Air-Gap might be better, especially since W-2's don't have a heat crossover anyway.

Doesn't Indy or someone else make an aluminum dual plane for W-2's as well as Mopar?

Chrysler and/or Mopar racers did that to a few LD340's in the infancy of the W-2 program before there were any manifolds for them.