EXPENSIVE AS HELL !!
49 usd for the pump and 71 go get it here

Question:
Can I use a 235 or earlier 261 pump and just plug the pipe that goes to heater since the heater is not working anyway, and use the only pipe from the earlier pump to the bypass tube on the thermostate house ?
Advice please
Yes, I have done this on two engines. In fact, one of the engines came that way from the factory (on a 1960 school bus).
I also used small-truck 235 thermostat housings, in order to have the hose diameters matching the smaller radiator. You will want to use you original thermostat housing.
If the thermostat does not have a hole drilled in it (to allow a little water flow at all times, drill a 1/8" hole in the thermostat).