I understand your point, but a Dominator on an adapter isn't necessarily a true test. The intake manifolds which are designed for a Dominator usually have the plenum designed differently.

Also, 4500 intakes are usually designed as "race" intakes with raised runners and other changes. This isn't always the case though, some vendors like Indy just machine the same intake differently for the 4500 carb. On the other hand, Edelbrock intakes are usually a totally different design for 4500 carbs.

You could spend money on an adapter and not see any performance increase. But a different intake with a Dominator might pick up a bunch of power.