While battleing a cold weather condensation issue on my mostly stock 49 216 I decided to up the thermostat from a 160 to a 180 and add a 4lb pressure cap and over the 4 months or so since the cooling system has been working great. (knock on wood).
I also added an overflow tank and it seems to work great also.
I did have to add alittle JB Weld to plug a small pin hole on the top radiator tank but otherwise the entire cooling system, including the heater core, seems to handle the 4lb pressure fine.
When the engine is cold the radiator will draw antifreeze from the overflow tank until the level in the tank is at the very top (no air gap). When running the radiator will vent enough coolant to the tank to where the coolant level in the radiator is approx 1"-2" lower. I can open the radiator cap during operation or right after shutdown and all I hear is air suction escaping. Per the stock gauge the temps never rises past the "0" in the 180 indicator.
The jury is still out come the heat of the summer but I've had no problems yet (again, knock on wood).
Dave
