If memory serves: ID number on the plate is 12R-4770B and the butterflies have "172" stamped on them the bore diameter is 1 5/8". Vacuum secondary. From searching the internet I believe the replacement is the 112-117. You may want to read on this site under carb section about a engineering change done around 72 to the plate giving it more "beef". A purist is going to want to find an era correct piece.
If function over form is your preference, meaning you do not care how it looks, welding can be done. Make sure you run a file over mating surfaces to true them up afterwards.