This is an NOS 116295 late style dowel bolt. This is one of the two styles of dowel bolts that hold the flywheel to the crankshaft. This is a very rare find and still in the cosmoline. (well some of it). It takes two of these per crankshaft. Here are the measurements The threaded end is 1/2" X 20 and 1/2" long. The smooth shank that goes through the flywheel is 9/16 and 1/2" long the head is 2/8" tall. This sale is for one bolt.   QTM Parts