A single throttle body system (fuel sprayed from a single source) will provide the same mixture distribution as the carburetor on the same manifold.
Since the venturi is no longer relevant, TB air flow can be greater than the original carburetor with the same throttle disc size.
As has been discussed, there is no reliable method to control mixture using port injection; the siamese ports + asymmetrical firing order of cylinders 1 & 2 and 5 & 6 (which are not equal but mirror images of the 240°-480°-240° intake cycles) are not suitable. The siamese but regular 360°-360° # 3 & 4 interval may be better, but not significant.
Downside:
1. $$$
2. learning curve
3. road-side repair is almost impossible, stores don't carry these spares
