Dart Running Hot?

Checking the thermostat is always a good (first) idea to do.

But, unlike the rest of the 'info' above here... unless you want to risc blowing headgaskets or waterhoses, burn up the life of your oil quickly, yeah then running with 210F maybe fine...

For me it's not. 180-190 is the max I want to see on a gauge.

It's true a fresh engine can have tight clearances but these should not cause an engine to run 30 degrees hotter than normal.

Since the engine has been rebuild;
- Any chance the timing is off (too late)?
- Camshaft-timing installed wrong?
- Vacuum leak?