I'm thinking the same as panic.
With a C-to-C of 2.925" (measured) versus 2.9375" (specified), the carburetor flange may fit well enough if the intake studs are not slightly bent or are slightly off center.
The 1.5" or even a 1.572" throttle bore doesn't make sense unless someone took a 216 Rochester B wielded the flange holes closed and re-drilled new ones.
Maybe the carburetor was made the day after a Canadian holiday.
