Questions about Fan Clutch

[Isaiah92260]

I was reading threw forums and online, and realized I've never thought about my fan clutch, or do I even have one? I don't know too much about them and I'm hoping if someone could explain what do they do and what are they for? And if I possibly should replace mine? I have a 67' I6 250, 4.1L, with a aluminum Radiator that sits 1 inch from the fan, I don't have a fan shroud yet, but I am going to by a universal one this week from EBay, does anyone think that I should get one? Maybe I over looked it, my truck sitting at idle can go from 190 to 210, and I've seen it go to 230 and I got scared and shut it off, this was a month ago when it happened, but it was 115 outside that day in the desert.