73 dart a/c heater hose?

I am doing a 73 Swinger back to original. It is a 318-2brl with A/C. The heater hose nipple coming out of the manifold is for 5/8" hose which then goes to the heater valve, then to the firewall. The problem I have is that the original heater valve has 1/2" nipples, as does the heater core. So how was the 1/2" hose connected to the 5/8" manifold nipple. The manifold is the original and only has 3/8"NPT threads for the 5/8" nipple????? Anyone got pics??