I have a 1986 iroc z with a carbed 305 everything is stock. I have a one inch copper radiator and had a 15 inch electric fan I believe it ran hot and overheated and boiled over a couple of times so I installed a big block flex fan on the motor in place of the electric fan. Now it runs at 100 on the streets on a cool day and 160ish on a hot day. I have a 195 therm and still the same radiator. Is this too cold for a motor even though the therm doesn't open? The fan is a beast and blows all the heat out through my Cowell scoop. Is this bad for the motor? Please help!
Car runs perfect nothing seems to be wrong with new engine fan.

 

I would venture a guess that your temperature gauge is incorrect

 

An engine running at 100 degrees is impossible. I don't care how big your fan is, the coolant inside the engine will be above 100 literally within a minute after the engine is started.

 

Yeah that's what my brother said (he works for an engine shop and builds race motors) I guess i'll have a look at those. I think i'll also add a second temp gauge that measures the heat of the heads will that be more accurate or not necessary?

 

I have mine in the intake manifold. I trust that to be closer to "engine coolant" temperature, as the coolant in the head can register hotter due to the radiant heat from the exhaust ports and manifolds/headers. Plus the heads can tend to run hotter than the block by nature anyway. Run both if you want, then you can keep an eye on head temps as well.

 

Putting a back up gauge is always a good idea. However, your stock sending unit is already in the head, so that is what you are reading. My guess is something is out of whack on that connection....or the sending unit itself.