The May 1978 release of AC/DC s third international album Powerage marked the debut of bassist Cliff Williams - who had taken over from Mark Evans following Evans sacking a year before in May 77. With its harder riffs, it followed the blueprint set by 1977 s Let There Be Rock and only one single was released from the record, Rock 'n' Roll Damnation/Sin City . An appearance at the Apollo Theatre, Glasgow during the Powerage tour was recorded and released as If You Want Blood You've Got It , and many fans consider the album AC/DC s most underrated work it remains too the final album from the Bon Scott era to have been produced by Vanda & Young.