Check the lower hose to see if obstructed,or collapsing under running conditions.
a lot of manufactures put a spring inside to prevent collapse.
Ford makes a pusher fan as well as conventional fan, pulling air through the radiator,-- is it installed correctly?
( I've seen that mistake)
check that the water pump is actually circulating the coolant.
( can you see into the radiator to affirm flow?)
Is the system air logged someway??
Some engines are best started and then coolant added so as the pump puts it
into all passages.
Just some ideas to possibly to help.
