My big block sits on 180 to 190 most of the time but sees 200 if stuck in traffic for extended period some times (not often). Are these temps OK ? I use Castrol edge oil 30 to 50 weight changed regular.

Those temps are fine IMO. Big blocks can run hotter than that without any problem.

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I wouldn't worry unless it starts to get to 230*-240*, IMO.

And if it does start to climb in REALREAL heavy traffic, just increase the rpms a little and it will cool down....turning heater of with fan also helps.

Turning the heater on should also help.

the heater will help etc....but bottom line u dont have a problem