From what I can see, and maybe I am looking at it wrong, That is the same type of lower housing that is used on the car 55-58 235s, probably the 59 -63 motors, very likely others. That upper hose outlet is not a rare part or anything but part of the heating system for some vehicles with 235s. For example, on a 57 car, the Hose goes from the thermostat housing to the heater control valve, when the valve is opened, water flows through the heater core and then exits, and goes to the water pump. On passenger car pumps for that year there is only one boss. But the two hole pumps were sold to be used in that application and applications that did not have an outlet on the therm housing. The pump on my 261 has two holes, heater return hose is plumbed into upper hole. Thermostats are the same as other gm products. I can probably get you the stant, tuff stuff or other part numbers.
Taking another look at the photo, is the boss for the hose in the upper or lower part of the housing? If it’s in the upper, disregard the above, lol. I don’t think I have ever seen an upper housing with a outlet boss in it!
Just asking here, but why are you bypassing or trying to run without the thermostat?
Last edited by Dragsix; 03/03/2018 9:50 PM.
