I'm looking at the 1967 Chevelle Assembly Manual for this. It shows no heater hoses at all, instead for the small block V8 it shows what appear to be pipe plugs inserted into the heater hose openings of the water pump.
I installed a heater in a southern pickup that never had a heater and there were pipe plugs in the engine. I had to remove them and install the nipples for the heater hoses. I changed the water pump rather than try to get the plug out. It wouldnt cooperate and a small block pump was cheap at the time.
