ok guys i have fitted a fiesta turbo engine into my mk4 escort and i am using the fiesta turbo rad a coolent hoses the only problem i have is fitting the header tank my escort one sits on the drivers side arch and the fiesta one sits on the suspension turret so my pipe for the header tank is in the wrong place and from what i belive the water is gravery fed from the header tank to the hoses now if i use my escort header the water will be running upstream

 

just use the escort one, it's not really gravity fed as such.
just make sure the top of the header tank is the hghest point in the car's cooling system.

 

where the fiesta tank joins the system is in the totally wrong place but there was a spare inlet on the rad near the top i have just plumbed it to here do you think this will be ok? also on the thermostat side you have a large pipe to rad a small pipe to top of the expansion tank (overflow) and the 3rd pipe does this go to the heater matrix ??