Rebuilt slant 6 overheating

I had my slant six from my 67 dodge dart rebuilt , I had the original old radiator cleaned and roded out . After five minutes of running on idle, the temperature reads at 195°-210° degrees. What is the operating temperature for a slant six? is that considered a little too warm or overheating? I read that timing could actually cause overheating !? Help! I need advice .