First City Industries, Beverly Hills, said it will sell the subsidiaries to Valor PLC of Britain for $400 million cash and warrants to purchase 2 million shares of Valor's common stock. In addition, First City, controlled by the Belzberg family of Canada, will purchase $35 million of Valor's convertible preferred stock. The combined common shares and preferred stock, if converted, would give First City a stake of less than 5% in Valor. Valor makes home products. Nutone makes built-in electric products for homes, and Yale produces door hardware.