Today I spent some time tidying up the engine bay. I removed the old heater hose which snaked from the rear of the engine block around toward the front.
The set-up was a bit curious, because there were no hoses connected to the heater core through the firewall. Also, since the engine came with what I believe to be the original cast iron fuel pump, which doesn’t have an outlet for a hose to the heater core, I plan to rationalize/correct/simplify the routing of heater hoses when I put this all back together. Namely, the outlet at the rear of the block will be connected via a short length of 1/2″ heater hose into the lower inlet of the heater core.
Then another longer section of heater hose will snake out of the upper heater core outlet, around the valve cover on the left side and turn right next to the thermostat housing and then run down into a new inlet connect on the new water pump.