[FWB]

yes most of our cars, the rad is lower than the highest point of the cooling system in the block. the ford purge tank allows for that. or a purge tank of any type mounted as the highest point.

i have a cylindrical purge tank mounted forward, it is the highest point but i still get air trapped in the intake manifold, i installed the little valve and fixed the issue. i fill and top off at my purge tank.