 730 AM is a Canadian and Mexican clear-channel frequency.AM 730 in Dallas began operations on August 1, 1957, as Top 40 music station KBCS.After a few years of competing with 1190 KLIF and 1480 KBOX for the Top 40 audience with limited success, the station changed calls to KKSN ("Kissin'") in 1959, evolving into an R&B format over the coming months and taking the new calls KRZY ("Crazy") in 1960.