340 overheating problem

So guys just an update.
Put a new mechanical auto meter gauge on it. Still getting overheating issues.
I feel like its an air pocket. ( I could be completely wrong!!) but after every cruise once the engine has cooled down, the fluid drops about 2-3inches.
So I add more water every time.

It seems to be staying cooler for longer now. But once she gets above 195-200, the temp just keeps rising.

Engine is running richer then i want right now. Timing is @ 34 total.

I'm running out of ideas. This problem happens going down the road @ 50mph. Not just idling in traffic.
The only thing left to do I change thermostat or add another fan. And not 100% sold either of those is gonna fix anything. I know the thermostat is opening. (About 185).