This is a vintage K R Wilson tool, the crankshaft plier S216 for use with the Ford V-8 "60" engine. The tool is designed for testing crankpin bearing installations after the connecting rod caps are tightened in place. The jaws of the tool grasp the flange of the bearing insert and turn it in the connecting rods. The mechanic learns by experience if it is correctly installed, by the way it feels when turned. The tool is listed in the 1940 K R Wilson catalog, with instructions that it is... not to be used with 1939 or 1940 engines. This was an important tool, as it allows the bearing insert to be tested after installation. If not detected, an incorrectly installed bearing insert will fail. K R Wilson of Buffalo New York was the official maker of specialty professional mechanics tools for Ford service, and they only made two tools like this, the other being the V131.