We highly recommend using a stretch gauge when installing rod bolts and other fasteners where it is possible to measure the length of the bolt after tightening. It is the most accurate way to determine the correct pre-load in the rod bolt. Measure the fastener prior to starting, and monitor overall length during installation. When the bolt has stretched the specified amount, the correct preload, or torque has been applied. We recommend you maintain a chart of all rod bolts, and copy down the length of the fastener prior to and after installation. If there is a permanent increase of .001'' in length or more, or if there is deformation, the bolt should be replaced immediately.
ARP offers a highly accurate stretch gauge with a dial indicator that reads in increment of .0005''. Features extra heavy springs for consistent repetition. Comes with a heavy-duty, insulated plastic carrying case for protection A must for any serious engine builder.