Another cooling system tip:
I have not tried thisd myself (yet) but it does make sense when you think about it...
STEAM: steam must be controlled by adding a restrictor at or near the ENTRANCE to the radiator.
Use a washer with a 3/4 inch ID for V8 engines.
The restriction causes the waterpump to pressurize the tube going to the radiator so the hot coolant will not "flash" to steam until it reaches the radiator, where it can condense.
I got this tip from Kennedy Engineering, with one of their engine/trans axle adapter kits. They included a tip sheet for keeping mid engined cars cool. A coupl e of things stressed on the sheet was keeping the air bled out of the system via a line from the rad to the surge tank,,,and preventing steam (air) from originating to start with.
I hope this helps.
On my project,,, I am planning on using one of the Davies/Craig elec water pump systems, and gutting my stock mechanical pump (& eliminating the stock thermostat).