Offenhauser Dual Port Bore Diameter and Carburetor Clearance

1927 Dodge roadster highboy build. It won't be towing anything but two people, :p but it will be a hot rod for street use that won't see over 5,500 rpm with the cam and will like power in the lower range. I've read on here that the Dual Port is a great intake for streetability on 273s/318s. If I come across a dual plane Equa-Flow for a good price, that's an option too.