Abstract: A cylinder block fixture for securing a workpiece is disclosed. The cylinder block fixture includes a base and clamping members. The clamping members are positioned apart at a distance facing each other on the base. Each of the clamping members includes a support plate at one end and a hand wheel at another end. Each of the support plates comprises a shaft, support bars, and support rods facing the opposite clamping member. The support rods extend from the support bars. The shafts at the support plates receive a camshaft housing of a workpiece. The workpiece includes a cylinder block. The support rods secure the workpiece. The hand wheel rotates and causes the workpiece to rotate. The workpiece rotates to align and take reference from a main bore or a pan rail surface of the workpiece to perform machining operations on the workpiece.