Header/Expansion tank setup

[Simeon]

Can you tell me how the plumbing for a header tank differs from the plumbing to an expansion tank?
I feel I need an expansion tank setup as it is physically impossible to have the tank higher than the heater matrix in the Westfield.
My engine setup is a RV8 3.5, offy manifold, edelbrock carb

[SuperV8]

My understanding is a header tank is a sealed system, the tank needs to be the highest point in the cooling system. An expansion tank has a different cap arrangement and bleeds off excess coolant into a tank, as the engine cools it will then draw this expelled coolant back into the system. This arangement can also be anywhere in the system, but you still need a filling cap at the top of the system, usually in the rad.

I have a Dax Rush V8 and there is just room to have the header tank as the highest point in the cooling system. Need to make sure you have enough 'expansion gap' in the top of the tank so it doesn't over pressurise.

Tom.