Sure looks like an old Ford 4N tracker's generator ! check it with a piece of tin, see if it has any residual magnetism. Itll be very low on outside of iron casing. IF there is any you're in luck .
Generator's of those days are very robust, not as efficient as today's alternators.
The little black box on outside is the regulator (probably) will have adjustable points in there.
The magnets inside were NOT very strong! similar to the ceramic of today, only curved.
I imagine you will not have any issues or it over speeding on you
.
It also looks like the spring setup was a tilt up to take it out of high high wind speeds.
I would also guess a 3 bladed prop setup could be used, BUT the tilt-up would probably need serious re-work.
Nice find!!
