This lower unit/gear case is from a 1958 Johnson 10 HP and will fit 1958-1963 10 HP as a unit, even swap, using the driveshaft that comes with it.
It turns freely, has an excellent skeg and straight anti-cavitation/ventilation plate. It will most likely need the prop shaft seal and shift rod o-ring replaced. Many parts from this can also be used on 5-1/2 and 7-1/2 HP from about 1956.
Phone number is a landline so doesn't accept texts. Leave a clear message with a number and I'll get back to you as soon as I can. Thanks.