I am driving a 74 F100 with a 390. I pulled the old thermostat last night. It didn't have the round copper do hickey on it. The replacement does. Which direction does the copper piece go?

 

the copper piece is the temp sensor it goes in the engine, the point goes towards the radiator.

 

You might want to find out where the rest of your old stat went b4 it jams up somewhere.

 

Thank you.Any suggestions?
The radiator lines were clear so is the water pump opening.

 

I've seen a few come apart over the years and I've pulled a couple out of blocks I had apart, but I've never seen one get stuck in the pump or cause any problems, so I wouldn't lose any sleep over it. the only moving part in there is the WP and the inlets are so thin I don't think a very large piece could get to it.

 

Another good tip is to drill a 1/8 inch hole in the flat area of the stat before installing. It will help eliminate any air in the system, and allows a small amount of flow during the cold starts.
Mark