Abstract: A clamshell type grill having an upper cooking platen mounted on a platen support arm for swinging movement between a lower cook position overlying a lower cooking platen and a raised position inclined upwardly from the lower cooking platen. The upper platen is manually operable to its lower cook position in which an arm stop in the arm engages an arm stop abutment and a pneumatic clamp cylinder is arranged to press and hold the platen support arm in its lower cook position. The upper platen is mounted on the platen support arm for limited floating movement in a direction perpendicular to the upper platen and adjustable platen stops on the platen support arm are arranged to engage platen stop abutments on the upper platen to limit downward movement of the upper platen to a preset lower position relative to the platen support arm and thereby control spacing of the upper platen from the lower platen.