Abstract: A unitary tool and method for adjusting and measuring the valve stroke in an injection blow mold core rod assembly which utilizes a lock/star nut and cam/hex nut arrangement to limit valve stroke. The tool is mountable on the end of the core rod and includes a pair of centerless hollow wrenches which can independently engage and rotate the star nut and cam nut, respectively. The tool also includes a push rod located within the wrenches which can be placed in contact with the hex nut so as to transmit the position of the hex nut and hence any movement of the core rod valve assembly on which the hex nut is fastened. A dial indicator is carried by the tool and arranged so as to have its sensor rod in position to be contacted by the push rod.