quote Garry in Tampa:
The 9.5 horse power outboard OMC built from 1964 through 1970 used the 4 bolt gear case used on the 1958 through 1963 10 Horse model. . . 😉
I believe the gearcase insides can used with 1960’S 10hp , but I don’t think the 9.5hp can bolt directly on a 10hp.
Edit: The shift rod connection is different. I forgot add this and Garry picked up my slack…..lol Thanks Garry 🙂