 Both ships exceeded their designed speed of during their sea trials; "Fusō" reached from and "Yamashiro" exceeded that with from .During their 1930s modernization, the Miyahara boilers on each ship were replaced by six new Kanpon oil-fired boilers, fitted into the former aft boiler room, and the forward funnel was removed.The Brown-Curtis turbines were replaced by four geared Kanpon turbines with a designed output of .