This is the stock (0°) dowel that locates the sprocket to the camshaft on the Ford 1600 Kent pushrod engine. Dowels are also available in 1 to 9° offset (Part No. 161-40-Size) to advance or retard cam timing.
This dowel fits the stock (unmodified) Ford sprocket with a 5/16" diameter hole. If your sprocket has an oversize (7/16") hole, your engine was set up for this dowel plus an offset "button" (a ring that fits around the dowel). Offset buttons are no longer available, but you can still change cam timing by using an offset dowel along with your existing button. If your button is missing, you will need to replace the camshaft sprocket.