Hello all. I have a 71 Riv GS 455. It runs well but I am wondering about the operating temperature. It has aftermarket gauges, including a temp. gauge. On a 90 degree day, driving down the Interstate for, say, 15 minutes, at a speed of 70 with the AC on, the gauge registers 220. When stopping in traffic it rises to nearly 230. Is this normal or too high? The overflow tank registers full. The radiator was replaced by a previous owner in 2007 (only about 2000 miles ago and the car has been exercised regularly since then). All thoughts are welcome! Thanks.