Is there a 8.33 KHz spacing slide-in replaceable unit available for the Bendix/King KTR-908?
No, unfortunately, Honeywell did not address the 8.33 kHz issue for their KTR-908 as Collins did for their VHF-21/22 series radios. Southeast Aerospace suggests retrofitting the KTR-908 radios with the VHF-22C radios with CTL-22C controls.