just ask for a rebuild kit for an autolite 1100/1101.
there were two different needle valve assemblies on those carbs, but the air horn gasket, spark control valve, acc. pump diaphragm fit both types and its subtypes.
motorcraft, hygrade and GP-sorensen offer generic kits and come with parts for both 1100 and 1101, covering both auto and stick versions.
however, "'65-'68 mustang 200ci" works most of the time for the guy behind the counter.
Should the parts monkey dare to inquire about the carb's ID tag (which your carb lacks, a common state after all these years), just tell 'em:
C50F E
B 5GA
that should do nicely.