I just purchased my 1969 Firebird and have a question about the front end. The previous owner replaced the upper and lower A frame bushings, upper and lower ball joints, rear springs, front and rear shocks and larger front sway bar. The vehicle has power steering which is too easy with turning the steering wheel. The problem is when I drive the car it swerves when it hits semi rough road. I can be driving it with no problems when all of a sudden it will swerve to the left or right. Any ideas what needs to be repaired? The tires are BFgoodrich and in pretty good shape with plenty of tread. Any help would be appreciated. Thanks