While in cruise flight the private pilot experienced a total loss of engine power. The pilot attempted an engine restart, but could not restore engine power. The pilot then elected to perform a forced landing to a plowed field. Upon touchdown, the gear contacted ruts in the ground resulting in a collapse of the landing gear. An examination of the airplane revealed that the housing encasing the fuel selector had been recently replaced with an incorrect housing which impeded movement of the fuel selector to all fuel tanks. The pilot reported that post-maintenance test flights did not detect the incorrect installation.