The early ODs were all cast iron. Based on the blank VIN pad and 67 casting date on the housing I would suggest it ks a hodge podge of parts built into a 67 or 68 case, and was probably put into an OD bellhousing or aftermarket blow proof bell , thus the adapter ring. The only way to truly know is to count the ratios. If you want to sell the OD shift rods and tabs I might be interested .
