Gets hot and stalls out
Just so we're on the same page.
This is about where I'd expect the gage to be after a short drive and the engine still running.
On a longer drive at interstate speeds, or in stop and go, a reading past center would not be surprising.
As long as its stable, and not rising under either condition (driving at interstate speeds or stuck in traffic) its within the norm.
1975 Valiant Operator's Manual. page 10.