My buddy has a 1963 hydrodyne with a 90 HP volvo penta stern drive. He needs a prop hub for it. he is willing to buy the entire prop if he needs to. Need to find some "old heads" to help him out. The boat runs great but the hub went bad. I have attached photos he sent me of what he has. Michigan Wheel Brass prop SMC 897 MICHIGAN 2114 INSIDE DIAMETER 3/4 INCH OUTSIDE DIAMETER 3-1/3 INCH
I may have what you need. When I get home on Tuesday, I'll measure one of the nos hubs I bought and let you know. I am very confident it is the right one with twelve splines.