help with heater hose routing

I need help figuring out which line feeds the supply line to the heater core and where does the return line route to from the heater core . I am working on a 1970 302 and the previous owner removed all of the hoses and i am unable to locate an adequate diagram in Haynes or Chiltons any one have any ideas . thank you in advance  

Its not really critical JKB. There are two fittings, one on the water pump and one in the manifold. Since the heater core is a single pass  small radiator it can flow either way. For early mustangs(and I assume its the same for later model, the pump hose goes to the top fitting and the manifold hose to the bottom fitting. So the water flows out to the heater core and back into the manifold. Switch them around and it still flows that way..lol.  

i always ran the manifold hose to the top core fitting and the pump hose to the bottom core fitting  

The original Mustang shop manual shows the factory recommended routing. In chapter 16, page six, figure 10-6 Ford recommends routing the V-8 manifold hose up over the carb choke housing and on to the bottom hole in the firewall to the heater core. The top hose from the heater core goes through the top hole in the firewall and is routed straight to the water pump fitting. It probably doesn't matter but if you are going for "correct" then there it is.  

With the early cars heater core mounted vertical, the only thing that occurs to me is with the water coming from the intake and going to the bottom of the core might be to prevent an air bubble situation from happening. Filling the core from the bottom would push the air out and up to the waterpump. Filling from the top could trap air and the core not fill completely. I've observed glass gas filters mounted vertically that would have a bubble trapped in the filter ( my HD ). I added more gas line and positioned it horizontally and the bubble disappeared.