The 7028213 is for the 327/350hp engine with the manual transmission. Not sure if the Corvette used a different number for the small block application. Might want to post that question on the Corvette Forum.
All of the early Chevy carburetors used small main airbleeds. They came with main jets from .064 to .071", and used "B" series metering rods. Most will have the APT system in the baseplate, except for very early units....Cliff