A slide-in or drop-in cooking range includes an upper cooktop in the form of a module suspended above an oven cavity. For installation purposes, the upper cooktop can be vertically repositioned relative to the oven cavity to assure proper alignment with the countertop and avoid damage to the cooktop as a result of combined thermal and mechanical stresses over time. The disclosure is particularly applicable to ranges employing glass cooktops having a periphery designed to rest upon edge portions of a countertop and contemplates various mechanisms to perform the cooktop repositioning function, including select mechanisms for locking, ratcheting and biasing the cooktop to establish a desired vertical position for the cooktop.