Abstract: A preassembled cam lock assembly comprising is disclosed which includes a housing defining a throughbore configured to receive an interchangeable lock core. A tail piece is fixedly secured on a rear face of the housing. The tail piece defines a stepped bore including an arc-shaped cutout. Each end of the arc-shaped cutout defines a stop surface. A cam driver is configured to be rotatably retained in the stepped bore of the tail piece. The cam driver includes a first end defining an arc shaped lost motion slot and a second end adapted to engage a cam. The cam driver has a plurality of spaced bores which are dimensioned to receive a driver pin which is movably positioned within the cutout of the tail piece between the stop surfaces. A cam is secured to the second end of the cam driver adjacent the tail piece.