With V8 being available across all models (Chevelle 300, Malibu, and Malibu SS), it appears time ran out. A handful may have been built at the very end and/or engineering cars survived and sold. Looks to be slim chance for a RPO assembly.
Jan '64 (listing L76)
May '64 (327 Released, Hold on L76)
June '64 (L76 pulled from list, bullet and space still there)
Paul