Edelbrock 1405 carb

No adapter necessary....although Edelbrock does make a thin metal spacer to assure there are no leaks about the secondary bulges. BUT, you don't even need that if you use the wide perimeter gasket like in @rumblefish360's photos up there^^^^^^. Even still I recommend it because I've seen them bolt on and work great and the suck that gasket out because there's such a small amount of contact area back there. This is it.

Carb Adapter #2732 for Edelbrock Manifolds Only, Square Bore-Spread Bore .100in

No need for all that thick 1/2" or 3/4" stuff. That will do the trick and be on there forever.