I've built a number of hipo small blocks (furd not chev) and I don't consider 210 deg "overheating". You are at least 20 deg from "hot" in MY book... My current 351w with cam heads and goodies runs 195 all day
Point of logic, if the water spends more time in the radiator shedding heat, then it also spends more time in the engine picking up heat, offsetting any benefit of spending any additional time in the radiator. Temperature differential is the biggest issue, the greater the delta T, the greater the rate of heat transfer. As the coolant temperature drops in the radiator, the rate of heat transfer also drops, reducing efficiency. Rather than have the coolant remain in the radiator, it is more efficient to have it return to the engine to remove more heat and bring it back to the radiator to release it, fast. The faster the better. This is why a high flow rate is more efficient than a lower flow rate.
The Jalopy Journal
