A seat back support assembly comprises a vehicle engaging member and a seat back receiving member. The vehicle engaging member is configured to be secured to a vehicle body. The vehicle engaging member includes a supporting section. The seat back receiving member includes (i) a base that is adjustably coupled to the supporting section, and (ii) a receiver that is coupled to the base, the receiver being configured to receive the seat back. The base is alternately positioned in a first vertical position and a second vertical position relative to the supporting section. When the base is in the first vertical position, the seat back is at a first height relative to the vehicle seat. Alternatively, when the base is in the second vertical position, the seat back is at a second height relative to the vehicle seat that is different than the first height.