A method of assembling a mirror head for a vehicular interior rearview mirror assembly includes providing a mirror casing, a mirror reflective element at the mirror casing, and a toggle mechanism, which includes a body portion and a toggle lever joined to the body portion. A lower pivot mount of the toggle mechanism is inserted into a lower receiving portion of the mirror casing and an upper pivot mount of the toggle mechanism is inserted into an upper receiving portion of the mirror casing. An outer surface of the body portion corresponds with adjacent outer surfaces of the mirror casing, and, when the toggle lever pivots relative to the lower receiving portion of the mirror casing, the mirror casing pivots relative to the body portion to flip the mirror head between a first orientation and a second orientation.