hi my name is stan and i have a question

Ive read alot of good info in these forums there great. well i found a forum about heating and thermostats so i ran my own tests at home found out that my t-stat was stuck open has been for a while because my temp never got above the one line above the 40 line so i changed it got a 176 deg F (80.c) and now the car run great never ran better wow amazing what a little t-stat can do
so heres my question if my car runs between the 80 line and the one above it which i dont know the value of that line can some one please tell me what the next line above 80 is and if my car is running in a safe range