The Wilwood Aero brake kit for 1965–1968 Chevrolet Impala applications with a drum spindle is specified as the Aerolite 6R package and includes a 14-inch vented GT rotor. The listing names the Aerolite caliper family and the 14-inch rotor diameter, so use those specifics to confirm fitment with classic Impala front conversions that accept 14-inch vented rotors and compatible spindles.
Wilwood 65-68 Chevrolet Impala W/ Drum Spindle Aerolite 6R - 14 in Vented GT Rotor