The pilot reported that during the landing roll with a constant crosswind, the airplane veered left of the runway centerline. He applied right rudder control and braking action which resulted in an over correction. The airplane entered a right ground loop which rotated the airplane about 270-degrees. The fuselage sustained substantial damage near the main landing gear and firewall area. The pilot reported no preaccident mechanical malfunctions or failures with the airplane that would have precluded normal operation.