On the Dom he used an HVH 4 hole tapered 4150-4500 adapter and he said he’s never seen it loose power. It’s usually worth 10. So maybe it’s more the spacer than the carb.
When I was in the building my 434 Brett Miller told me to go Dominator on a Dominator flanged intake. He also told me to not use an adapter on a 4150 intake, just stay with a 4150.