Edelbrock LD4B ?s

#2 I have an Edelbrock 1406 carburetor (currently on my buddy's truck so I can't measure it) to put on this manifold. Does the 1406 mount using the studs currently on the manifold, or will I need to move the studs to the inside holes?

It will fit. All the current Edelbrock carbs have enough holes to mount on any intake except the dominator series intakes.
I do very seriously suggest the use of an Edelbrock "thick" carb insulator gasket as this prevent heat from getting Into the carb and boiling the fuel.