Z Rock was a nationally syndicated Hard Rock/Heavy Metal radio network based out of Dallas, Texas. They existed from 1986 to 1996. I remember listening to our local Z Rock affiliate, 96.5 WZRZ out of Cincinnati which went on the air in 1990. At least one station still uses the Z Rock name and logo despite the network being defunct--KRQR from Orland, California. A surprising number of Z Rock stations lived on the AM dial including these three:
KMTW - Las Vegas, Nevada. Currently Spanish as KRLV.
KKZR - Houston, Texas. Currently News/Talk KNTH.
WLPZ - Westbrook, Maine. Currently carries a Sports format as WRED.
My son displaying a vintage, shark-logoed Z Rock t-shirt along with some apparent roid rage.