Hoping someone can help me here, I have a 76 C3, It has been fitted with a worked up LS6 454 with approx 11-1 Comp, approx 600HP Using the standard small block hood with scoop, aluminum radiator from Be Cool Radiators and a fully shrouded high speed 15"thermo fan, also a high flow 160 deg thermostat. I cant get the bugger to run under 200 deg city and 210 hwy. Any advise from people who have similar mods?

really a trial and error at this point. How old is the thermostat? Is is a heavy duty one? No air in the radiator system? May need to purge it. could be many things really. Water pump issue?

I don't think that is bad anyways, I think that most here would agree also. One thing did you get a tune done after all those things were done?

Imho,
How About A 180* Thermo Instead. The Water Will Stay In The Engine Longer And Pick Up More Heat.
Example:
If You Removed The Thermo Completely, Water Would Not Stay Long Enough To Pick Up Heat And You Can Over Heat.
Just My Opinion, Don't Cha Know.

200-210 isn't bad for a big block. But you could get it a few degrees cooler. Remember, you need to get the air to go through the radiator. Check the seals around the radiator. Also make sure the fan is into the shroud deep enough to pull the air. Are you running a lower front air-dam? The air dam forces air up and into the radiator.

But if you have a true 11-1 comp LS6, 200 -210 is not bad at all. The more hp you make, the more heat an engine will produce. If your timing is off or running a lean carb this will allow the engine to build more heat.

I have a 500hp 327 and it runs 200-220 on the street.