Yes, I'm pretty sure the Alfetta's had electric fans. I've got an Alfetta Haynes manual at home so I'll look and see what that says. Incidentally it's worth looking out for an Alfetta Haynes manual as the engine overhaul chapter is far better than anything you can find for the 105 and it is the same lump.
I employed a deeply scientific method for deciding when my fan kicked in.
I ran the engine up to normal temp (bang on halfway on my dial) and as it crept slightly over, that's where I made the fan come in!! Clever eh? Unfortunately I can't give you a specific value on that as my switch is adjustable but you need to make sure your fans are kicking in a good way above your thermostat opening value as you don't want the two fighting each other.