More carb questions/suggestions

Still looking for options on least finicky carburetor for the '68 383 im putting in my 66 fury going with a performer intake . I found a guy that has the two carburetors city take $15 a piece for them. Looked up the numbers, and it looks like they are both 600 CFM.
1 what is the difference in these?
2 is 600 cfm enough for my 383
4 any other advice is appreciated.
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View attachment 141257
Author: Bayoulee