It is a 235. I should have mentioned that! It has an 'accessory' style heater that mounts on the firewall. A donut style heater core with the blower motor in the center. I found the heater shown in a Chevrolet Accessory manual. But that manual did not describe where the hoses were to be installed. On this engine, one heater hose was connected to a port on the water pump. The other was connected to a port on the thermostat housing. So maybe the mystery part was used for the heater possibly before the PO found the option of either the water pump or thermostat housing port?
So, a follow-up question. Where the pipe is connected to the block, could this be actually cast into the block? (and threaded?) I have looked at photos of blocks and never saw that option.
Thanks again!
