Abstract: A clamping system for use in supporting automotive vehicles in secured relation above a floor surface includes an adjustable height pedestal having a base member with a ram member entered in sliding relation therein. Laterally inclined convergent internal side walls serve as guides to keep in mutually centered relation a pair of vertically extending mating faces of the base member and the ram member. These mating faces have laterally extending tooth members standing proud of their surfaces in mutually interengageable relation to lock the members together against vertical displacement. Clearance within the base member sufficient for the lateral disengagement of the respective tooth members permits vertical adjustment of the ram member relative to the base. Jacking screws extending laterally within the base serve to hold the ram member in tooth engaged relation with the mating face of the base, in a locked, pre-set position of a predetermined height.