A lot. Everything. No.
The DCOE flange needs to be cut in half, then the throttles will be split apart and welded to the flange. The throttles will also need some of the vacuum ports plugged and the inlets need to be turned to mate with the velocity stacks. The throttle outlets will probably need a round in the lathe as well to make port matching easier.
The cast manifold is clearly of dubious quality and will probably need to have the faces milled flat.
Since the throttles will be split, the fuel rail blank will be machined to fit the new spacing. AN fittings will also get welded on and mounting brackets will also need to be fabricated.