greatest improvement you can make to a gas engine is to lock out the timing. Running an advance curve at lower rpms means the timing is retarded and puts most of the heat into the cylinder heads which ups the coolant temps.
I ran a 8.50's with a 468 on pump gas, used to stress staging at 220 when running alky cars backing up slow to build heat. I then locked the dizzy out and ran restrictors under the water pump outlets to slow the coolant flow. The moroso pumps circulate too fast at idle as they are constant flow. Water has a high surface tension and doesn't absorb or dissipate heat well without an additive, so slowing the flow down, giving it chance to absorb heat and discipate it through the rad is essential. A temp sensed controller on the pump speed would also be good.
